Apparatus and method for manufacturing organic EL display device

ABSTRACT

Provided are a producing apparatus and a producing process which make it possible to obtain effectively an organic EL display device capable of suppressing the generation of dark spots for a long time even in a high temperature environment. Therefore, an apparatus for producing an organic EL display device comprises a first unit for carrying a supporting substrate in, a second unit for heating at least the supporting substrate before forming an organic luminescence medium, thereby performing a dehydration treatment, a third unit for forming the organic luminescence medium and an upper element, and a fourth unit for sealing the periphery of the apparatus with a sealing member, wherein the first unit is arranged between the second unit and the third unit, a first carrying device is set up in the first unit, and a second carrying device is arranged between the third unit and the fourth unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for producing an organicEL display device, and a process for producing an organic EL displaydevice. More specifically, the present invention relates to a producingapparatus making it possible to produce an organic EL display device:capable of suppressing the generation of non-luminescence areas ornon-luminescence spots, which may be referred to dark spots, in pixels;and a process for producing such an organic EL display device.

The “EL” described in the claims and the specification is anabbreviation of “electroluminescence”.

2. Description of the Related Art

Hitherto, various sealing means and moisture-proof means in organic ELdisplay devices have been investigated to exclude the effect of moisturein the atmosphere and suppress the generation of non-luminescence areas,non-luminescence spots and the like in luminescence areas at the time ofdriving the devices.

It is also studied that an organic EL display device is produced withoutbeing exposed to the atmosphere. Such a producing apparatus is disclosedin JP-A-No. 8-111285, 10-214682 or 10-335061.

As illustrated in FIG. 20, in a producing apparatus 250 for an organicEL display device disclosed in JP-A-No. 8-111285, plural vacuum chambers111 to 116 for working are connected to the periphery of a vacuum device110. A movable arm 102 for carriage is disposed inside the vacuumdevice. Thus, a substrate 104 can be moved while the vacuum device andthe working vacuum chambers are under a reduced pressure condition.

Therefore, respective layers of an organic EL element can be formed onthe substrate in the respective working vacuum chambers while thesubstrate is passed through the single vacuum device. In other words, anorganic EL display device can be produced without being exposed to theatmosphere from the respective film-depositing step to the step offorming a protective film.

As illustrated in FIG. 21, an apparatus for producing an organic ELdisplay device disclosed in JP-A-No. 10-214682 comprises independent 1st-nth working vacuum chambers 222 a to 226 a, and 1st-nth carrying vacuumchambers 222 to 226 connected to the working vacuum chambers throughgate valves 222 d to 226 d, respectively. The carrying vacuum chambers222 to 226 are horizontally connected to each other through gate valves222 c to 227c. A substrate and so on can be transferred from a first drybox 221, which is an inlet, to a second dry box 227, which is an outlet,by means of robot arms 222 b to 226 b set up in the respective carryingvacuum chambers.

Accordingly, it is possible that respective layers of an organic ELelement are formed in the respective working vacuum chambers and theunfinished organic EL element can be successively moved in therespective working vacuum chambers through the carrying vacuum chamberswhile the working vacuum chambers are in a reduced pressure state. Inshort, an organic EL display device can be produced without beingexposed to the atmosphere from the step of depositing its films to asealing step.

As illustrated in FIG. 22, an apparatus for producing an organic ELdisplay device, disclosed in JP-A-No. 10-335061, comprises a vacuumchamber 315, a vacuum device 307 connected to the vacuum chamber, acarrying and pressing means 316 for carrying an organic EL element 309or a sealing member 312 in the vacuum chamber, a hardening means 311 forhardening an adhesive layer 313 between the organic EL element 309 andthe sealing member 312.

It is therefore possible to form respective layers of the organic ELelement inside the vacuum chamber 315 and further harden the adhesivelayer 313 with the hardening means (ultraviolet-ray exposure device) 311in the state that the sealing member 312 prepared inside the vacuumchamber is positioned and then pressed from the above by means of thecarrying and pressing means 316. In short, an organic EL display devicecan be produced without being exposed to the atmosphere from the step ofdepositing its films to a sealing step.

However, in the organic EL display device producing apparatus disclosedin JP-A-No. 8-111285, the number of the working vacuum chambers(vapor-depositing chambers or sputtering chambers) arranged around itsvacuum tank is as large as, for example, five. Thus, a problem that theproducing apparatus becomes large-sized arises.

No unit for removing water from an organic EL wafer wherein atransparent element, an organic film and so on are formed on a glasssubstrate is set up. It is therefore difficult to lower the watercontent in an organic luminescence medium in the resultant organic ELdisplay device. Thus, a problem that dark spots as non-luminescenceareas are easily generated arises.

A problem that sealing is insufficient is also caused since a protectivefilm is formed on the organic EL wafer and subsequently the resultant isexposed to the air.

The organic EL display device producing apparatus disclosed in JP-A-No.10-214682 comprises the 1st -nth working vacuum chambers, the 1st -nthcarrying vacuum chambers and the first and second dry boxes, and theyare horizontally connected to each other. Thus, this apparatus has aproblem that it becomes markedly large-size.

This producing apparatus has the first dry box. However, the first drybox is a space where the water content is controlled into a low valueand no heating device is set up. Thus, water contained in a substrateand so on cannot be positively removed.

Therefore, it is difficult to lower the water content in the organicluminescence medium in the resultant organic EL display device. Thus, ithas still been difficult to suppress the generation of dark spots and soon as non-luminescence areas and obtain a high luminescence brightnessfor a long time.

The organic EL display device producing apparatus disclosed in JP-A-No.10-335061 has no water-removing means, that is, no function for removingwater contained in a substrate and so on positively. Therefore, it isdifficult to lower the water content in the organic luminescence mediumin the resultant organic EL display device. Thus, it has still beendifficult to suppress the generation of dark spots and so on asnon-luminescence areas and obtain a high luminescence brightness for along time.

As illustrated in FIG. 23, an organic EL display device producingapparatus 400 disclosed in JP-A-No. 2000-133446 comprises load sidereceipt chambers 412 and 413, a load side normal-pressure carryingchamber 411, a load chamber 421, a vacuum carrying chamber 431,film-depositing chambers 432 to 435, an unload chamber 441, an unloadside normal-pressure carrying chamber 451, unload side receipt chambers452 and 453, and an airtight working chamber 454, and is characterizedin that an inert gas atmosphere having a water content of 100 ppm orless is filled at least into the unload chamber 441 and the unload sidenormal-pressure carrying chamber 451. JP-A-No. 2000-133446 alsodiscloses that in the load side receipt chambers 412 and 413, asubstrate and any organic material on the substrate are preferablyheated to remove water from them.

However, in the disclosed organic EL display device producing apparatus,the position into which the substrate is carried and the position inwhich the substrate is heated are common. Therefore, the apparatus has aproblem that in the case in which the load side receipt chamber is onceheated, a next substrate cannot be carried thereinto until thetemperature of the load side receipt chamber falls. Since the positioninto which a substrate is carried and the position in which thesubstrate is heated are common and further the load side normal-pressurecarrying chamber is arranged after the heated load side receipt chamber,it is difficult to reduce the pressure of the load side receipt chamber,cool the chamber, or set up a precision balance therein. Therefore, aproblem that it takes much time to remove water from the substrate andso on sufficiently or carry out a dehydration step arises.

Thus, it is suggested that plural load side receipt chambers aredisposed. However, there arise problems that the whole of the producingapparatus including a heating device and a precision balance becomeslarge-scaled and the performances of resultant organic EL displaydevices are scattered because of a scattering in heating temperatures inthe load-side receipt chambers.

Furthermore, in the disclosed organic EL display device producingapparatuses, the position into which a substrate is carried and theposition in which the substrate is heated are common. Therefore, it isimpossible that the position where the substrate is heated and theposition where the substrate is cleaned are conversely made common.Thus, the apparatuses have problems that the whole of the apparatusesincreasingly becomes large-scaled and further the substrate absorbswater at the time of the transfer of the substrate from thesubstrate-heating position to the substrate-cleaning device so thatdehydration effect is lowered.

Thus, the inventors eagerly made further investigations on suchproblems. As a result, it has been found that by setting up awater-removing unit separately from the position into which a supportingsubstrate is carried and removing water positively from the substrateand so on through heating treatment, the water content in an organicluminescence medium can be markedly lowered, so that the generation ofdark spots and the like, as non-luminescence areas, around pixels can begreatly suppressed.

Therefore, an object of the present invention is to provide an organicEL display device producing apparatus making it possible to obtaineffectively an organic EL display device capable of suppressing thegeneration of dark spots and the like even if the device is driven for along time.

Another object of the present invention is to provide an organic ELdisplay device producing process making it possible to obtaineffectively an organic EL display device capable of suppressing thegeneration of dark spots and the like even if the device is driven for along time.

SUMMARY OF THE INVENTION

[1] According to the present invention, provided is an apparatus forproducing an organic EL display device which has at least a lowerelectrode, an organic luminescence medium and an upper electrode, on thesupporting substrate, and the periphery of the device being sealed witha sealing member,

the apparatus comprising:

a first unit for carrying the supporting substrate in,

a second unit for heating at least the supporting substrate beforeforming the organic luminescence medium, thereby conducting adehydration treatment,

a third unit for forming the organic luminescence medium and the upperelectrode, and

a fourth unit for sealing the periphery with the sealing member, and

carrying units being set up between the respective units. Thus, theabove-mentioned problems can be solved.

Namely, this producing apparatus is made to comprise the second unit forconducting the dehydrating treatment positively, which is different fromthe location into which the substrate is carried. Therefore, the watercontent in the organic luminescence medium after the organic EL displaydevice is fabricated is easily adjusted. Thus, it is possible to obtaineasily the organic EL display device superior in endurance wherein thegeneration of dark spots and the like as non-luminescence areas ismarkedly reduced.

[2] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the first unit is arranged between thesecond unit and the third unit.

According to this producing apparatus, the substrate and so on can berepeatedly reciprocated between the second unit and the third unitthrough the first unit. Therefore, film-deposition and dehydration canbe repeated any number of times.

According to this producing apparatus, the first unit can function as abuffer at the time of the heating in the second unit and a reduction inthe pressure in the third unit.

[3] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the second unit is composed of a heatingroom and a cooling room.

This structure makes it possible to cool the substrate promptly in thecooling room even if the substrate is heated under a reduced-pressure inthe heating room.

[4] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the second unit is provided with atleast one of an inert gas circulating device, a pressure-reducingdevice, and a cooling device.

This structure makes it possible to use the inert gas while thedehydrating treatment by heating is conducted. Therefore, thedehydrating treatment can be more effectively conducted in the statethat the organic EL display device is not substantially exposed to theatmosphere.

This structure also makes it possible to conduct the dehydratingtreatment by heating in a reduced pressure state. Therefore, thedehydrating treatment can be made more effective.

This structure also makes it possible to cool the substrate easily afterthe dehydrating treatment by heating. Therefore, the time until thesubstrate is transferred to the next step can be markedly reduced. Inthe case that the dehydrating treatment by heating is conducted in areduced pressure state, natural cooling does not advance. Thus, thiscooling device is a particularly effective means.

[5] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the first unit is provided with at leastone of an inert gas circulating device, a pressure-reducing device, anda cooling device.

This structure makes it possible to use the inert gas in the first unit.Thus, the substrate and so on are not exposed to the atmosphere whenthey are transferred or cooled.

This structure also makes it possible to make the first unit into areduced pressured state. Therefore, the substrate and so on can betransferred to the third unit in a reduced pressure state.

This structure also makes it possible to cool easily the substrate inthe first unit after the dehydrating treatment by heating in the secondunit. Thus, the time until the substrate is transferred to the next stepcan be markedly reduced.

[6] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the fourth unit is connected to thefirst unit.

This structure makes it possible to arrange the 1st to 4th units in aradiant state and make the first carrying unit in common with the secondcarrying unit. Thus, the producing apparatus can be made small.

[7] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the second unit is made in common withthe fourth unit.

This structure makes it possible to save spaces for the first and fourthunits. Thus, the producing apparatus can be made smaller.

[8] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the third unit is a vacuum evaporationdevice having plural evaporation sources for evaporating plural samplessimultaneously or successively.

This structure makes it possible to form the respective layers of theorganic EL element while a given vacuum state is kept. Therefore, thewater content in the organic luminescence medium can easily be adjusted.Moreover, the producing apparatus can be made smaller than the case inwhich the third unit is composed of plural evaporation devices and soon.

In order to obtain the organic luminescence medium and so on that have auniform thickness, the substrate and the plural evaporation sources arepreferably rotated independently.

[9] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the third unit comprises a buffer room,a vacuum evaporation device, and a sputtering device.

This structure makes it possible to select appropriately the method fordepositing each of the layers of the organic EL element dependently onthe kind of the material thereof.

Since the buffer room is set up, the vacuum evaporation device can beconnected to the sputtering device through the buffer room. Therefore,the degree of vacuum in the respective rooms can easily be adjusted.

The use of this buffer room makes replacement of plural substratespossible. Therefore, it is easy to different substrates simultaneouslyin the vacuum evaporation device and the sputtering device.

[10] In the organic EL display device producing apparatus of the presentinvention, it is preferred that the third unit further comprises aplasma-cleaning device. This structure makes it possible to make theorganic EL display device more minute and better in endurance.

[11] Another embodiment of the present invention is a process forproducing an organic EL display device, using any one of theabove-mentioned producing apparatuses, comprises the steps of:

carrying a supporting substrate into the first unit,

using the carrying device to-transfer the carried-in supportingsubstrate from the first unit to the second unit,

heating the transferred supporting substrate in the second unit toconduct a dehydrating treatment,

using the carrying device to transfer the dehydrated supportingsubstrate from the second unit to the third unit,

forming an organic luminescence medium and an upper electrode in thethird unit,

using the carrying device to transfer the supporting substrate on whichthe organic luminescence medium and the upper electrode are formed fromthe third unit to the fourth unit, and

sealing the periphery of the organic EL display device with a sealingmember in the fourth unit.

This process makes it easy to adjust the water content in the organicluminescence medium after the organic EL display device is fabricated.It is therefore possible to obtain effectively the organic EL displaydevice wherein the generation of dark spots and the like is markedlyreduced.

[12] In the organic EL display device producing process of the presentinvention, it is preferred that the second unit comprises a heating roomand a cooling room, the supporting substrate is heated in the heatingroom to conduct a dehydrating treatment, and the dehydrated supportingsubstrate is cooled in the cooling room.

The process makes it possible to cool the substrate easily in thecooling room of the second unit even if the substrate is heated anddehydrated in a reduced pressure state in the heating room of the secondunit. Thus, the time for producing the organic EL display device can bemade short.

[13] A further embodiment of the present invention is a process forproducing an organic EL display device, using the above-mentionedproducing apparatus, comprises the steps of:

carrying a supporting substrate into the first unit,

using the carrying device to transfer the carried-in supportingsubstrate from the first unit to the second unit,

heating the transferred supporting substrate in the second unit toconduct a dehydrating treatment,

using the carrying device to transfer the dehydrated supportingsubstrate from the second unit to the third unit through the first unit,

forming an organic luminescence medium and an upper electrode in thethird unit,

using the carrying device to transfer the supporting substrate on whichthe organic luminescence medium and the upper electrode are formed fromthe third unit to the fourth unit, and

sealing the periphery of the organic EL display device with a sealingmember in the fourth unit.

Since there is used the producing apparatus wherein the place which thesupporting substrate is carried into and the place which the substrateis dehydrated are different from each other, the producing time can bemade short. Moreover, the flexibility of the arrangement of theproducing apparatus is improved. Furthermore, the water content in theorganic luminescence medium can easily be adjusted.

[14] A still further embodiment of-the present invention is a processfor producing an organic EL display device, using the above-mentionedproducing apparatus, comprises the steps of:

carrying a supporting substrate into the first unit,

using the carrying device to transfer the carried-in supportingsubstrate from the first unit to the second unit,

heating the transferred supporting substrate in the second unit toconduct a dehydrating treatment,

using the carrying device to transfer the dehydrated supportingsubstrate from the second unit to the third unit through the first unit,

forming an organic luminescence medium and an upper electrode in thethird unit,

using the carrying device to transfer the supporting substrate on whichthe organic luminescence medium and the upper electrode are formed fromthe third unit to the fourth unit via the first unit, and

sealing the periphery of the organic EL display device with a sealingmember in the fourth unit.

This process makes it possible to make the producing time short, improvethe flexibility of the arrangement of the producing apparatus, and makethe adjustment of the water content in the organic luminescence mediumeasy.

[15] An additional embodiment of the present invention is a process forproducing an organic EL display device, using the above-mentionedproducing apparatus, comprises the steps of:

carrying a supporting substrate into the first unit,

using the carrying device to transfer the carried-in supportingsubstrate from the first unit to the second unit,

heating the transferred supporting substrate in the second unit toconduct a dehydrating treatment,

using the carrying device to transfer the dehydrated supportingsubstrate from the second unit to the third unit,

forming an organic luminescence medium and an upper electrode in thethird unit,

using the carrying device to transfer the supporting substrate on whichthe organic luminescence medium and the upper electrode are formed fromthe third unit to the fourth unit which is in common with the secondunit through the first unit, and

sealing the periphery of the organic EL display device with a sealingmember in the fourth unit.

This process makes it possible to make the producing time short, improvethe flexibility of the arrangement of the producing apparatus, and makethe adjustment of the water content in the organic luminescence mediumeasy.

[16] In the organic EL display device producing process of the presentinvention, it is preferred that the supporting substrate dehydrated inthe second unit is transferred to the first unit and cooled, andsubsequently the supporting substrate is transferred to the third unit.

The cooling in the first unit in this way makes it possible to cool thesupporting substrate effectively even if the substrate is dehydrated ina reduced pressured state in the second unit. Thus, the time until thesubstrate is transferred to the third unit can be shortened.

The cooling of the substrate dehydrated in the first unit makes itpossible to dehydrate another substrate simultaneously in the secondunit. Thus, productive efficiency can be improved.

[17] In the organic EL display device producing process of the presentinvention, it is preferred that the organic luminescence medium isformed in the third unit; the supporting substrate on which the organicluminescence medium is formed is then transferred to the second unit toconduct the dehydrating treatment; and subsequently the supportingsubstrate is again transferred to the third unit to form the upperelectrode.

This process makes it easier to adjust the water content in the organicluminescence medium after the organic EL display device is fabricated.It is therefore possible to obtain effectively the organic EL displaydevice wherein the generation of dark spots and the like is markedlyreduced.

[18] In the organic EL display device producing process of the presentinvention, it is preferred that the water content in the organicluminescence medium after the sealing with sealing member is performedis set to 0.05% or less by weight.

This process makes it possible to obtain effectively the organic ELdisplay device wherein the generation of dark spots and the like ismarkedly reduced under the storage not only at room temperature but alsoat a high temperature (for example, 80° C.).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating an apparatus for producing an organic ELdisplay device (No. 1);

FIG. 2 is a view illustrating an apparatus for producing an organic ELdisplay device (No. 2);

FIG. 3 is a view illustrating an apparatus for producing an organic ELdisplay device (No. 3);

FIG. 4 is a sectional view of an organic EL display device (No. 1);

FIG. 5 is a sectional view of an organic EL display device (No. 2);

FIG. 6 is a sectional view of an organic EL display device (No. 3);

FIG. 7 is a sectional view of an organic EL display device (No. 4);

FIG. 8 is a sectional view of an organic EL display device (No. 5);

FIG. 9 is a sectional view of an organic EL display device (No. 6);

FIG. 10 is a schematic view of a first unit;

FIG. 11 is a schematic view of a second unit;

FIG. 12 is a schematic view of a third unit (No. 1);

FIG. 13 is a schematic view of the third unit (No. 2);

FIG. 14 is a schematic view of a third unit (No. 3);

FIG. 15 is a schematic view of a fourth unit;

FIG. 16 is a view illustrating an apparatus for producing an organic ELdisplay device of a second embodiment;

FIG. 17 is a graph showing a relationship between the water content inan organic luminescence medium and the ratio of a luminescence area;

FIG. 18 is a view for explaining a full automatic moistureabsorption/desorption measuring device;

FIG. 19 is a moisture measuring chart resulting from measurement withthe full automatic moisture absorption/desorption measuring device asshown in FIG. 18;

FIG. 20 is a view illustrating a conventional apparatus for producing anorganic EL display device (No. 1);

FIG. 21 is a view illustrating a conventional apparatus for producing anorganic EL display device (No. 2);

FIG. 22 is a view illustrating a conventional apparatus for producing anorganic EL display device (No. 3); and

FIG. 23 is a view illustrating a conventional apparatus for producing anorganic EL display device (No. 4).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, embodiments of the present invention will bespecifically described hereinafter. The drawings, which are referred to,merely illustrate the size, shape and arrangement relationship ofproducing apparatuses schematically to such an extent that the presentinvention can be understood. Therefore, the present invention is notlimited to only illustrated examples. In the drawings, hatching, whichrepresents a cross section, may be omitted.

[First Embodiment]

As is schematically illustrated in FIG. 1, an apparatus 100 forproducing an organic EL display device in a first embodiment comprises:

a first unit 21 for carrying a supporting substrate in,

a second unit 23 for heating at least the supporting substrate beforeforming an organic luminescence medium, thereby conducting a dehydrationtreatment,

a third unit 22 for forming the organic luminescence medium and an upperelement, and

a fourth unit 24 for sealing the periphery of the device with a sealingmember,

wherein the first unit 21 is arranged between the second unit 23 and thethird unit 22, a first carrying device 25 is set up in the first unit21, and a second carrying device 27 is arranged between the third unit22 and the fourth unit 24. Respective structures of the first carryingdevice 25 and the second carrying device 27 are not illustrated, butonly moving directions thereof are represented by arrows.

Referring appropriately to FIG. 1, the following will describe thestructure of the producing apparatus 100 of the first embodiment, theoperation thereof, an organic EL display device obtained using thisproduction device 100, and so on.

1. First Unit

{circle around (1)} Function and Structure

The first unit 21 illustrated in FIG. 1 is an inlet for carrying asupporting substrate etc. in, and is a mediating space for the secondunit 23 and the third unit 22. For this reason, the first unit 21 isconnected to the second unit 23 and the third unit 22 through eachpartition 26.

As is separately illustrated in FIG. 10, therefore, the first unit 21preferably comprises, for example, a housing 42, a substrate stage 43, acooling device 48, a hot plate 44, a supporting base 47, dry gascirculating devices 35 and 36, a vacuum pump 40, a dew point hydrometer45, and full automatic absorption/desorption measuring device 46.

A non-illustrated carrying device (not shown), such as a movable armcapable of attaining reciprocating motion in the directions representedby an arrow 25 in FIG. 10, is preferably set up.

The housing 42 among these constituent members is a member for receivingat least the supporting substrate 1 and the substrate stage 43.

The hot plate 44 and the cooling device 48 are arranged below thesubstrate stage 43, and are made to adjust (heat or cool) thetemperature of the supporting substrate 1 and so on so that thesubstrate and so on heated with the second unit 23 can be cooled.

The dry gas circulating device 35 and 36 are set up to prevent contactwith the atmosphere by introduction of an inert gas with adjustment ofthe dew point with the dew point hydrometer 45.

The dew point hydrometer 45 and the full automatic moistureabsorption/desorption measuring device 46 are set up since there may bea case in which the water content in a luminescence medium is measuredin the first unit 21.

The first unit 21 may also be made to an outlet for carrying an organicEL display device obtained by sealing in the fourth unit 24. In otherwords, in the case of the producing apparatus illustrated in FIG. 1, theorganic EL display device after the sealing step in the fourth unit 24can be taken out from the fourth unit 24, but the organic EL displaydevice can be transferred to the first unit 21 through the third unit 22and can be taken out from the unit 21.

The volume of the first unit is preferably from ½ to 1/10 of that of thethird unit, and is more preferably from ⅓ to ⅕ thereof.

This is because if the volume of the first unit is more than ½ of thatof the third unit, it may take excessively much time to lower the vacuumdegree of the first unit when a substrate and so on are transferred fromthe first unit in an atmospheric pressure state to the third unit in areduced pressure state.

On the other hand, if the volume of the first unit is smaller than 1/10of that of the third unit, the size of substrates which can be treatedwith the present apparatus may be excessively restricted.

{circle around (2)} Arrangement

As illustrated in FIGS. 1 to 3, the first embodiment is characterized inthat the first unit 21 is arranged between the second unit 23 and thethird unit 22.

A first reason why such arrangement is carried out is that thearrangement makes it possible to come and go to a substrate and so onbetween the second and third units 23 and 22 through the first unit 21.In other words, the first reason is that this arrangement makes itpossible to perform dehydration treatment in the second unit 23 andfilm-deposition in the third unit 22 repeatedly through the first unit21.

For example, a substrate on which a lower electrode is set is subjectedto a given dehydration treatment in the second unit 23, and subsequentlythe resultant is transferred from the second unit 23 to the third unit22 through the first unit 21 to form a hole injection layer. Next, thesubstrate on which the hole injection layer is formed is againtransferred from the third unit 22 to the second unit 23 from the firstunit 21 and then subjected to a given dehydration treatment. Thus, thewater content in the hole injection layer is made to a given value orless. By repeating such a manner, the formation and dehydration of anorganic luminescence layer, the formation and dehydration of an electroninjection layer, the formation and dehydration of an upper electrode,and so on are performed so that the water content can be adjusted into avery low value before sealing.

A second reason why the above-mentioned arrangement is performed is thatthis arrangement makes it possible to perform dehydration treatment andfilm-deposition simultaneously or successively on plural substratesthrough the first unit 21.

For example, the first and second carrying devices 25 and 27 are set upin the first unit 21, and further a first substrate and a secondsubstrate to be treated are put on the respective carrying devices.Next, only the first substrate is transferred to the second unit 23 bythe first carrying device 25, to conduct a given dehydration treatment.The first substrate subjected to the dehydration treatment istransferred from the second unit 23 to the third unit 22 through thefirst unit 21 by the first carrying device 25. At the same time, thesecond substrate put on the second carrying device 27 is transferredfrom the first unit 21 to the second unit 23. In the third unit 22,film-deposition is performed on the first substrate at the same timewhen the second substrate can be subjected to a dehydration treatment inthe second unit 23.

A third reason why such arrangement is performed is that the arrangementmakes it possible to reduce the number of carrying devices. In otherwords, if the number of the carrying device(s) 25 set in the first unit21 is at least one, the carrying device 25 is used to make it possibleto transfer a substrate and so on between the second unit 23 and thethird unit 22.

Thus, such arrangement of the 1st to 3rd units 21, 23 and 22 permits theproducing apparatus to be small-sized.

A fourth reason why such arrangement is performed is that thearrangement makes it possible to produce a state that the second unit 23and the third unit 22 do not interfere with each other.

In other words, if the second unit 23 and the third unit 22 are directlyconnected to each other, it is feared that moisture and low molecularweight substances to be discharged outside by the second unit 23 invadethe inside of the third unit 22 or heat to be radiated outside isconducted into the third unit 22.

Thus, such problems can be solved by arranging the first unit 21 betweenthe second unit 23 and the third unit 22.

{circle around (3)} Carrying Device

One example of the carrying device is illustrated in FIG. 2, and themoving directions thereof are illustrated by arrows in FIGS. 1 to 3.This device 25 is preferably a device which is capable of fixing(gripping) a substrate and moving the position thereof. Therefore,examples thereof include a movable arm having a gripping portion and anexpansion and contraction portion, a robot arm, a movable rail, and arotating plate.

The number of the carrying machines 25 and 27 is not limited. The numberis preferably a value within the range of 1 to 5, and is more preferablya value within the range of 1 to 3. This is because as the number of thecarrying devices is larger, the number of substrates which can betreated can be made larger but the producing apparatus may belarge-sized or the size of the substrates which can be treated may belimited.

Dependently on the structure of the producing apparatus, the firstcarrying device 25 and the second carrying device 27 are preferably madecommon in light of the space thereof in the case that the first unit 21is directly connected to the fourth unit 24 as illustrated in FIG. 2 orin the case that the second unit 23 and the fourth unit 24 are common asillustrated in FIG. 3. Such a structure makes it possible to make theproducing apparatus more small-sized and make the operation of thecarrying device simple.

2. Second Unit

The second unit 23 illustrated in FIGS. 1 to 3 is a dehydrating unit(dehydrator) for dehydrating a substrate, an organic luminescencemedium, and so on.

As is separately illustrated in FIG. 11, the second unit preferablycomprises a housing 32, a substrate stage 33, a cooling device 38, a hotplate 34, a supporting base 37, dry gas circulating devices 35 and 36, avacuum pump 30, a dew point hydrometer 45, a full automatic moistureabsorption/desorption measuring device 46, and a plasma cleaning device39.

The housing 32 among these constituent members is a member for receivingat least the supporting substrate 1 and so on to be dehydrated, thesubstrate stage 37, and the dehydrator.

The hot plate 34 and the cooling device 38 are arranged below thesubstrate stage 33, and constitute a dehydrator wherein the temperatureof the supporting substrate 1 and so on is adjusted (heated or cooled)so that the dew point is adjusted and water is removed. An infrared raylamp is preferably set up instead of the hot plate 34 or together withthe hot plate 34 since heating can be attained for a short time.

The dry gas circulating devices 35 and 36 are set to remove water byintroduction of an inert gas with adjustment of the dew point with thedew point hydrometer 45. Therefore, the substrate and so on are notexposed to the atmosphere in the dehydration step.

The dew point hydrometer 45 and the full automatic moistureabsorption/desorption measuring device 46 are set up to measure thewater content in the luminescence medium.

Furthermore, the plasma cleaning device 39 is set to remove impuritiesadhering to the surface of the substrate or dust and obtain a stableorganic EL luminescence.

Accordingly, the following is preferred: an inert gas is blown againstthe supporting substrate and so on, fixed on the substrate stage insidethe housing, under a flow rate of, for example, 10 liters/minute, usingthe dry gas circulating device, and a dehydration treatment is conductedfor a given time while confirming that the dew point is −10° C. or lowerwith the dew point hydrometer.

A dehydration treatment is preferably conducted for 1 to 120 minutes asfollows: at the same or different time of the introduction of the inertgas, the heating device or the cooling device, such as the plate set upbelow the substrate stage, is used to control the temperature of thesupporting substrate into a given temperature, preferably a value withinthe range of 40 to 300° C., more preferably a value within the range of50 to 200° C., and still more preferably a value within the range of 80to 150° C. Particularly in the case that an organic film such as aninterlayer dielectric is beforehand formed on the substrate, thesupporting substrate is preferably heated in the range of 40 to 80° C.to prevent heat deterioration of the organic film.

At the same or different time of the introduction of the inert gas, thevacuum pump is used to adjust the degree of vacuum of the inside of thehousing, preferably into 13.3 Pa (0.1 Torr) or less, and more preferablyinto 0.00133 Pa (0.00001 Torr) or less.

In the case that at the time of performing plasma cleaning, argon andoxygen are used as the plasma gas, the flow rates thereof are preferablyset to 20 to 1000 sccm and 10 to 500 sccm, respectively, and thepressure thereof is preferably set to 0.1 to 10 Pa. It is also preferredto set the frequency of the high frequency wave (RF) at the time of theplasma cleaning to 13.56 MHz, set the output thereof to a value withinthe range of 10 to 200 W, and set cleaning time to a value within therange of 1 to 60 minutes.

The full automatic moisture absorption/desorption measuring device setin the dehydration unit is used to make it possible to measure the watercontent in the organic luminescence medium. Specifically, when the watercontent in the organic luminescence medium is measured, a part of theorganic luminescence medium is collected from the supporting substrateand then the above-mentioned weights A and B are measured so that thewater content can be calculated. The organic luminescence medium can becollected manually, or automatically using the carrying device.

Referring FIGS. 18 and 19, the following will describe the outline ofthe full automatic moisture absorption/desorption measuring device.

The full automatic moisture absorption/desorption measuring device 51illustrated in FIG. 18, which is one example of such devices, iscomposed of a circulating section A and a moisture measuring section B.They are divided in the drawing by a dot line.

The circulating section A is composed of a gas storing unit 68; a drygas circulating device 67 and a wet gas circulating device 66, which areconnected to forked portions of the gas storing unit 68; and acirculating path 61 for connecting these circulating devices 66 and 67to the moisture measuring section B. The circulating devices 66 and 67are operated by remote control from a control room 65 inside themoisture measuring section B.

On the other hand, the moisture measuring section B is composed of thecontrol room 65, a balance room 62, a comparative sample room 64(including a comparative sample plate), a dry box 65, an oil bath 52,and so on. A heating device 57 is arranged around the dry box 56. Atemperature sensor 54 for monitoring the temperature inside the dry box56 and a humidity sensor 55 for monitoring the humidity are set in thedry body 56 and near the balance 53 on which a measurement sample isput.

According to the full automatic moisture absorption/desorption measuringdevice 51, after the temperature and the humidity can be made constantby passing a dry gas supplied from the circulating section A through theoil bath 52, this dry gas can be introduced into the dry box 56 throughan inlet 58 and the temperature and the humidity inside the dry box 56can be kept constant by the heating device 57. A precision balance 63 isused in this state to measure the weight of the measurement sample, suchas a glass substrate which is put on the balance 53, in the control room65, with comparison with the comparative sample (reference) in thecomparative sample room 64.

FIG. 19 shows a measurement chart obtained by measuring the weight. Thetransverse axis thereof represents passage time (minute), and thevertical axis represents the weight (g) of the sample. According to themeasurement of this sample, the weight A was 554.440 mg, and the weightB was 554.300 mg. In this example, the humidity inside the dry box 56was controlled into 0%.

The weights A and B are preferably measured using the precision balanceset in the full automatic moisture absorption/desorption measuringdevice. The water content can also be measured by the method accordingto ASTM D570-63, thermal analysis (differential thermal analysis: DTA,or differential scanning calorimetry: DSC), or Karl Fischer technique.

3. Third Unit

The third unit 22 is a film-depositing unit for depositing the organicluminescence medium, the upper electrode, or the like on the surface ofthe supporting substrate or the like.

As is separately illustrated in FIG. 14, therefore, the third unit 22preferably comprises at least one vapor depositing device 60 and 61, asputtering device 62, an ion plating device, an electron beamevaporation device, a chemical vapor deposition (CVD) device, a metaloxide chemical vapor deposition (MCVD) device, a plasma enhancedchemical vapor deposition, or the like.

{circle around (1)} Vapor Deposition Device Capable of SimultaneousVapor Deposition

The third unit 22 is preferably a vapor deposition device capable ofsubjecting plural samples simultaneously or successively to vapordeposition.

Specifically, it is preferred that a vacuum deposition device 201 asillustrated in FIGS. 12 and 13 is used to evaporate plural evaporationmaterials (plural samples) simultaneously or successively from pluralevaporation sources 212A to 212F arranged oppositely to a substrate 203.

It is also preferred that using this vacuum evaporation device 201, arotation axis 213A for rotating the substrate 203 on its axis is set tothe substrate 203 and the evaporation sources 212A to 212F are arrangedapart from the rotation axis 213A for the substrate 203 to perform vapordeposition while the substrate 203 is rotated on its center.

The following will describe the. vacuum evaporation device 201illustrated in FIGS. 12 and 13 in more detail. The device 201 iscomposed of a vacuum tank 210, a substrate holder 211 for fixing thesubstrate 203, arranged at the upper side inside the vacuum tank 210,and plural (six) evaporation sources 212A to 212F in which evaporationmaterials are charged, arranged below the substrate holder 211 andoppositely to the holder 211.

In this vacuum tank 210, its inside can be kept in a reduced pressuredstate by an exhausting means (not illustrated). The number of theevaporation sources, which is six on the drawing, is not limited to six,and may be 5 or less, or 7 or more.

The substrate holder 211 has a holder unit 215 for supporting theperiphery of the substrate 203, and is made to hold the substrate 203horizontally inside the vacuum tank 210.

A rotation axis unit 213 for rotating the substrate 203 (on its axis) isvertically arranged at the center of the upper face of the substrateholder 211. A motor 214, which is a rotation driving means, is connectedto the rotation axis unit 213. By rotation operation of the motor 214,the substrate 203 held on the substrate holder 211 together with thesubstrate holder 211 rotate around the rotation axis unit 213.

In short, the rotation axis 213A of the rotation axis unit 213 isvertically set at the center of the substrate 203.

In this vapor deposition device, the shape of the substrate 203 is notparticularly limited. In the case that the substrate 203 is, forexample, in a rectangular and plate form as illustrated in FIGS. 12 and13, it is desired to satisfy M>(½)×L when the plural evaporation sources212A to 212F are arranged on the circumference of an imaginary circle221, the center of which is present at the rotation axis 213A of thesubstrate 203, the radius of the imaginary circle 221 is represented byM, and the length of one side of the substrate 203 is represented by L.When the lengths of the sides of the substrate 203 are different, thelongest length thereof is represented by L.

Such a structure makes it possible to make the incident angles of theevaporation materials, from the evaporation sources 212A to 212F, to thesubstrate 203 identical to each other. Therefore, the composition ratioof the evaporation materials can easily be controlled.

Such a structure makes it possible that the evaporation materials areevaporated with a constant incident angle to the substrate 203.Therefore, the evaporation materials are not subjected to perpendicularincidence, and the uniformity of the composition ratio in the filmsurface can be still more improved.

It is desired to arrange, in this vapor deposition device, therespective evaporation sources 212A to 212F at intervals of an angle of360°/n around the center of the imaginary circuit 221 when the pluralevaporation sources 212A to 212F are arranged on the circumference ofthe imaginary circle 221, the center of which is present at the rotationaxis 213A of the substrate 203, as illustrated in FIG. 12, and thenumber of the arranged evaporation sources 212A to 212F is representedby n.

In the case that the number of the arranged evaporation sources 212 is,for example, six, it is preferred that they are arranged at intervals ofan angle of 60° around the center of the imaginary circle 221.

Such arrangement makes it possible to form films successively from theplural evaporation materials on respective portions of the substrate 203in the manner that the films overlap with each other. It is thereforepossible to deposit thin layers whose composition ratio is regularlychanged in the thickness direction of the layers.

{circle around (2)} Device Wherein Both a Vapor Deposition Device and aSputtering Device are Used

As illustrated in FIG. 14, the third unit is preferably a device 22wherein both of the vapor deposition devices 60 and 61 and thesputtering device 62 are used.

Such arrangement makes it possible to select appropriately thefilm-deposition methods for the respective layers of the organic ELelement, correspondingly to the kinds of use materials. For example,about an organic material, a film therefrom is preferably depositedusing the vapor deposition device 60 and 61. About an inorganicmaterial, a film therefrom is preferably deposited using the sputteringdevice 62.

In the case that the third unit is preferably a device 22 wherein bothof the vapor deposition devices 60 and 61 and the sputtering device 62are used, it is preferred that a buffer room 64 is disposed and furtherthe vapor deposition devices 60 and 61, the sputtering device 62, or aplasma cleaning device 63 are connected to each other through the bufferroom 64 by means of connecting members 65, as illustrated in FIG. 14.Setting of the buffer room 64 in this way makes it possible to preventthe vacuum degree in the respective vapor deposition devices from beinglowered by adjusting the vacuum degree in the buffer room 64 even if thesubstrate is carried into the respective vapor deposition devices or thelike.

Setting of the buffer room 64 in this way also makes it possible toperform film-deposition, correspondingly to a desired organic EL displaydevice. Specifically, for one substrate, successive treatments can beconducted in the plasma cleaning device 63, the vapor deposition devices60 and 61, and the sputtering device 62. For another substrate, atreatment can be conducted in any one of the plasma cleaning device 63,the vapor deposition devices 60, and the sputtering device 62.

In FIG. 14, arrows A to D and F from the central position E of thebuffer room 64 represent respective advancing directions of thesubstrate. In the case that a carrying device (not illustrated) and, forexample, the vapor deposition devices 60 and 61 are used, it isadvisable to transfer the substrate in the direction of the arrow A orB.

{circle around (3)} Plasma Cleaning Device

As illustrated in FIG. 14, the third unit is preferably provided withthe plasma cleaning device 63.

Use of this plasma cleaning device 63 makes it possible to clean thesurface of the dehydrated substrate and so on more effectively in thesecond unit 23. Therefore, an organic EL display device superior inprecision and endurance can be produced.

Conditions for plasma-cleaning in the plasma cleaning device 63 are notparticularly limited. In the case that, for example, argon and oxygenare used as the plasma gas, the flow rates thereof are preferably set to20 to 1000 sccm and 10 to 500 sccm, respectively, and the pressurethereof is preferably set to 0.1–10 Pa. In the case that the frequencyof the high frequency wave (RF) is set to 13.56 MHz at the time of theplasma cleaning, it is preferred to set the output thereof to a valuewithin the range of 10 to 200 W. Under such plasma cleaning conditions,it is preferred to set cleaning time to a value within the range of 1 to60 minutes.

This is because pollutants, such as organic substances, adhering to thesurface of transparent electrodes made of ITO or the like can beeffectively removed without the surface being excessively damaged if theabove-mentioned plasma cleaning conditions are used. If theabove-mentioned plasma cleaning conditions are used, the surface of thetransparent electrodes can be reformed into an optimal state so thathole injection ability can be improved.

When the plasma cleaning device 63 is used, the substrate is preferablycleaned before film-deposition by the plasma cleaning device 63. It isalso preferred that plasma treatment is conducted in the same deviceafter film-deposition in order to remove low molecular weight substancesand so on.

{circle around (4)} Precision Balance

In order to set the water content (W) in the organic luminescence mediumafter it is deposited to 0.05% or less by weight for reasons that willbe described later, it is preferred to set up a precision balance, forexample, a full automatic absorption/desorption measuring device havinga precision balance.

However, there is a case in which organic films such as an interlayerdielectric, a flattening layer, a fluorescence medium and a color filterare present around the organic luminescence medium so that it isdifficult to distinguish the organic luminescence medium from the otherorganic films. In this case, the weight of the mixture which partiallycontains the organic films other than the organic luminescence medium ismeasured, and then the water content in the organic luminescence mediummay be calculated from a value obtained from the weight. This is becauseit has been separately proved that by setting the water content in sucha mixture to 0.05% or less by weight, a drop in the luminescence arearatio can be effectively prevented. Specifically, it can be consideredthat moisture by which the thus measured water content is defineddiffuses without being located in the organic films other than theorganic luminescence medium, for example, the interlayer dielectric, andthen invades the organic luminescence medium so that an equilibriumstate is caused and the water causes the organic luminescence medium orthe opposite electrode to be oxidized or deteriorated. It can betherefore considered that even if a mixture composed of, for example,the organic luminescence medium, the interlayer dielectric and so on iscollected, the water content in the organic luminescence medium is 0.05%or less by weight.

Thus, in the case that, for example, the interlayer dielectric isdeposited around the organic luminescence medium, it is advisable tocollect arbitrarily the organic luminescence medium and the interlayerdielectric as a mixture, measure the weights A and B about the mixture,and set the water content calculated from these weights to 0.05% or lessby weight.

However, dependently on the structure of the organic EL display device,the water content in the organic luminescence medium or the watercontent in the organic films comprising the organic luminescence mediumcan be roughly grasped without collecting the organic luminescencemedium.

Specifically, the weight C of the organic luminescence medium having thesupporting substrate and so on before drying, and the weight D thereofafter the drying are measured using the full automaticdesorption/desorption measuring device, and further the weight E of thesupporting substrate and so on other than the organic luminescencemedium or the weight E of the supporting substrate and so on other thanthe organic film comprising the organic luminescence medium, the weightE being beforehand measured using the full automaticdesorption/desorption measuring device, is obtained to estimate thewater content (W) in the organic luminescence medium or the organicfilms comprising the organic luminescence medium from the followingequation:W=[(weight C−weight D)/(weight D−weight E)]×1004. Fourth Unit

The fourth unit 24 is a sealing unit (sealing device) for covering theperiphery of the organic EL element obtained at the time of thefinishing of the third unit 22 with a sealing member in order to preventmoisture from invading the inside of the organic EL element.

As is separately illustrated in, for example, FIG. 15, the fourth unit24 preferably comprises a housing 52, a substrate stage 55, a hot plate54, a pressing device 53, an exposure equipment 51 for setting anadhesive, dry gas circulating devices 35 and 36, a vacuum pump 50, a dewpoint hydrometer 45, and a full automatic desorption/desorptionmeasuring device 46.

In other words, it is preferred to circulate a dry gas such as nitrogenor argon sufficiently inside the housing 52, using the dry gascirculating devices 35 and 36, cover the periphery of an organic element59 with a sealing member 58 in this state, and seal the peripherythereof with an adhesive 57, for example, a radical setting adhesive, acation setting adhesive, a thermosetting adhesive, or a moisture settingadhesive.

In order not to cause positional slippage when the adhesive 57 is set,it is also preferred to apply pressure at a pressing power of 9.8×10⁴ Pato 4.9×10⁵ Pa with the pressing member 53.

In order not to cause invasion of moisture from the interface betweenthe adhesive 57 and the sealing member 58, it is also preferred to add,to the adhesive 57, 0.1 to 5% by weight of a silane coupling agent suchas γ-aminopropyltrimethoxysilane or γ-glycydoxypropyltriethoxysilane.

In order to prevent invasion of moisture to the inside effectively, theconstituent material of the sealing member 58 is preferably the same asthat of the supporting substrate and is, for example, soda glass orquartz. The thickness of the sealing member 58 is preferably a valuewithin the range of 0.1 to 1 mm.

In order to make the creeping distance from the outside to the organicEL element 59 long, it is preferred to make a groove (not illustrated)in the substrate, fill the adhesive 57 thereinto, and press and fix thesealing member 58 thereto.

5. Connecting Unit

It is preferred that connecting parts 26 are arranged between the firstand second units, between the first and third units and between thesecond and third units, and are composed of gate valves, shuttermechanism (partitions) or the like.

These connecting parts 26 are preferably in synchronization with thefirst and second carrying device (not illustrated).

For example, in the case that the substrate is transferred from thefirst unit in an atmospheric pressure state to the second unit in anatmospheric pressure state, the first carrying device grasps thesubstrate and advances toward the second unit. In synchronization withit, the connecting part between the first and second units is opened. Itis therefore possible that the first carrying device passes through theconnecting part to reach the second unit and subsequently the devicestops the grasping of the substrate to put the substrate on a givenposition in the second unit.

In the case that the substrate is transferred from the first unit in anatmospheric pressure state to the second unit in a low pressure state,the connecting part between the first unit in the atmospheric pressurestate and the second unit in the low pressure state is first opened andfurther the first carrying device advances from the first unit to thesecond unit to grasp the substrate.

Next, the first carrying unit advances from the first unit to the secondunit in the state that the carrying unit grasps the substrate, and thenthe carrying unit stops in the second unit. Next, the connecting partbetween the first and second units is closed and further the vacuum pumpof the first unit is operated. When the vacuum degree of the first unitis equal to that of the third unit, the connection unit between thefirst and third units is opened and further the first carrying unitadvances again from the first unit in the low pressure state to thethird unit in the low pressure state in the state that the firstcarrying device grasps the substrate. Thus, the first carrying devicereaches the third unit and then stops the grasping of the substrate.Thus, the substrate can be put on a given position in the third unit.

6. Organic EL Display Device

The organic EL display device obtained with the producing apparatus ofthe first embodiment preferably has the following structure.

(1) Supporting Substrate

The supporting substrate (which may be referred to the substratehereinafter) in the organic EL display device is a member for supportingthe organic EL element, TFT and so on. It is therefore preferred thatthe substrate is superior in mechanical strength and dimensionalstability.

Specific examples of such a substrate include glass substrates, metalplates, ceramic plates, and plastic plates (such as polycarbonate resin,acrylic resin, vinyl chloride resin, polyethylene terephthalate resin,polyimide resin, polyester resin, epoxy resin, phenol resin, siliconeresin and fluorine resin substrates).

In order to avoid the invasion of moisture into the organic EL displaydevice, it is preferred that the substrate made of any one of the aboveis subjected to moisture-proof treatment or hydrophobic treatment byforming an inorganic film or applying a fluorine resin.

Particularly in order to avoid the invasion of moisture into the organicluminescence medium, it is preferred to make the water content in thesupporting substrate and the gas transmission coefficient thereof small.Specifically, it is preferred to set the water content in the substrateand the gas transmission coefficient to 0.0001% or less by weight and1×10⁻¹³ cc·cm/cm²·sec. cmHg or less, respectively.

In the first embodiment, the substrate does not necessarily havetransparency since EL luminescence is taken out from the side oppositeto the substrate, that is, from the upper electrode side.

(2) Organic Luminescence Medium

The organic luminescence medium can be defined as a medium comprising anorganic luminescence layer making EL luminescence possible byrecombination of an electron and a hole. This organic luminescencemedium can be made, for example, by depositing the following layers onthe lower electrode.

-   {circle around (1)} organic luminescence layer-   {circle around (2)} hole injection layer/organic luminescence layer-   {circle around (3)} organic luminescence layer/electron injection    layer-   {circle around (4)} hole injection layer/organic luminescence    layer/electron injection layer-   {circle around (5)} organic semiconductor layer/organic luminescence    layer-   {circle around (6)} organic semiconductor layer/electron barrier    layer/organic luminescence layer-   {circle around (7)} hole injection layer/organic luminescence    layer/adhesiveness improving layer

The structure {circle around (4)} among these structures is usuallypreferred since it can give higher luminescence brightness and issuperior in endurance.

{circle around (1)} Constituent Material

The luminescence material in the organic luminescence medium may be oneor a combination of two or more selected from the following:p-quaterphenyl derivatives, p-quinquephenyl derivatives, benzothiazolcompounds, benzoimidazol compounds, benzoxazol compounds, metal-chelatedoxinoide compounds, oxadiazol compounds, styrylbenzene compounds,distyrylpyrazine compounds, butadiene compounds, naphthalimidecompounds, perylene derivatives, aldazine derivatives, pyrazirinederivatives, cyclopenetadiene derivatives, pyrrolopyrrole derivatives,styrylamine derivatives, coumarine compounds, aromatic dimethylidenecompounds, metal complexes having an 8-quinolinol derivative as aligand, and polyphenyl compounds.

{circle around (2)} Water Content

In order to suppress the generation of dark spots effectively, the watercontent (W) in the organic luminescence medium defined by the followingequation is set to preferably 0.05% or less by weight, more preferably0.0001 to 0.04% by weight, still more preferably 0.0001 to 0.03% byweight, most preferably 0.0001 to 0.01% by weight.W=[(weight A−weight B)/weight B]×100

weight A: the weight of the organic luminescence medium collected fromthe organic EL display device, the weight being measured with the fullautomatic moisture absorption/desorption measuring device (with theprecision balance), and

weight B: the weight of the organic luminescence heated at 75° C. in adry box for 30 minutes, the weight being measured with the fullautomatic moisture absorption/desorption measuring device.

The weights A and B are preferably measured using the precision balanceset in the full automatic moisture absorption/desorption measuringdevice. The water content can also be measured by the method accordingto ASTM D570-63; thermal analysis (differential thermal analysis: DTA,or differential scanning calorimetry: DSC), or Karl Fischer technique.

There is a case in which organic films such as an interlayer dielectric,flattening layer, a fluorescence medium and a color filter are presentaround the organic luminescence medium so that it is difficult todistinguish the organic luminescence medium from the other organicfilms. In this case, the weights A and B are measured as the mixturewhich partially contains the organic films other than the organicluminescence medium, and then a value obtained from the weights may beused as the water content. This is because it has been separately provedthat by setting the water content in such a mixture to 0.05% or less byweight, a drop in the luminescence area ratio can be effectivelyprevented.

Thus, in the case that, for example, the interlayer dielectric isdeposited around the organic luminescence medium, it is advisable tocollect arbitrarily the organic luminescence medium and the interlayerdielectric as a mixture, measure the weights A and B about the mixture,and set the water content calculated from these weights to 0.05% or lessby weight.

Referring to FIG. 17, the following will specifically describe reasonswhy the water content in the organic luminescence medium is limited to avalue of 0.05% or less by weight.

FIG. 17 shows relationship between the water content in the organicluminescence medium (which may partially include some other organicfilm) and the ratio of change in its luminescence area by the generationof dark spots. Its transverse axis represents the water content (% byweight) in the organic luminescence medium, and its vertical axisrepresents the ratio of change in the luminescence area (the area of theluminescence area after the generation of dark spots)/the area of theluminescence area before the generation of the dark spots) as aluminescence area ratio.

In FIG. 17, the symbol ▴ represents the luminescence area ratio in thecase that the organic EL display device was allowed to stand at roomtemperature (25° C.) in the atmosphere for two weeks, and the symbol ●represents the luminescence area ratio in the case that the organic ELdisplay device was allowed to stand in a thermostat of 75° C. for twoweeks.

As is easily understood from FIG. 17, as the water content in theorganic luminescence medium is smaller, the value of the luminescencearea ratio trends to be larger. As the water content in the organicluminescence medium is larger, the value of the luminescence area ratiotrends to be smaller. It is however observed that the luminescence arearatio does not change linearly to the water content in the organicluminescence medium and if the water content is over 0.05% by weight,the luminescence area ratio is markedly low.

Therefore, by limiting the water content in the organic luminescencemedium to not more than a value of 0.05% by weight, which has such acritical significance, a drop in the luminescence area ratio can beeffectively prevented. In other words, the generation of dark spots canbe suppressed so that a high luminescence brightness can be obtained fora long time.

The luminescence area ratio trends to be smaller in the storage in thethermostat of 75° C. for two weeks than in the storage in the atmosphereat room temperature (25° C.) if the water contents under the twoconditions are the same. In the two standing conditions, however, aphenomenon that the luminescence area ratio is markedly low if the watercontent is over 0.05% can be observed.

Conversely speaking, by limiting the water content in the organicluminescence medium to 0.05% or less by weight, the generation of darkspots can be markedly suppressed not only under the standing conditionin the atmosphere at room temperature (25° C.) for two weeks but alsounder the standing condition in the thermostat of 75° C. for two weeks.It is therefore more useful to set the water content to a value of 0.05%or less by weight when the organic EL display device is used under ahigh temperature condition.

(3) Electrode

The following will describe the upper and lower electrodes. However,dependently on the structure of the organic EL element, the upper andlower electrodes may correspond to anode and cathode layers,respectively, or cathode and anode layers, respectively.

{circle around (1)} Lower Electrode

The lower electrode corresponds to an anode or cathode layer dependentlyon the structure of the organic EL display device. In the case that thelower electrode corresponds to, for example, an anode, it is preferredto use a metal, an alloy or an electrically conductive compound having alarge work function (for example, 4.0 eV or more), or a mixture thereof.Specifically, it is preferred to use one or a combination of two or moreselected from indium tin oxide (ITO), indium zinc oxide (IZO), copperindium (CuIn), tin oxide (SnO₂), zinc oxide (ZnO), gold, platinum,palladium and so on.

By using any one of these electrode materials, the lower electrodehaving a uniform thickness can be made using a method makingfilm-deposition in a dry state possible, such as vacuum evaporation,sputtering, ion plating, electron beam evaporation, CVD, MOCVD, orplasma CVD.

{circle around (2)} Upper Electrode

The upper electrode corresponds to an anode or cathode layer dependentlyon the structure of the organic EL display device. In the case that theupper electrode corresponds to, for example, a cathode, it is preferredto use a metal, an alloy or an electrically conductive compound having asmaller work function (for example, not more than 4.0 eV) than the anodelayer, a mixture thereof, or an inclusion thereof.

Specifically, it is preferred to use one or a combination of two or moreselected from sodium, sodium-potassium alloy, cesium, magnesium,lithium, magnesium-silver alloy, aluminum, aluminum oxide,aluminum-lithium alloy, indium, rare earth metals, mixtures of any oneof these metals and an organic luminescence medium material, mixture ofany one of these metals and an electron injection layer material, and soon.

(4) Intermediate Insulating Layer

The intermediate insulating layer in the organic EL display device ofthe first embodiment is present near or around the organic EL element(including peripheral elements such as TFT), and causes the unevennessof the luminescence medium or color filter to be flattened, so as to beused mainly as a flattened undercoat when the lower electrode of theorganic EL element is formed. The intermediate insulating layer is alsoused to attain electric insulation for forming highly minute wiringmaterials, electric insulation (prevention of short circuits) betweenthe lower and upper electrodes of the organic EL element, electricalinsulation or mechanical protection of TFT, electrical insulationbetween TFT and the organic EL element, and so on.

In the first embodiment, therefore, the interlayer dielectric may becalled a flattening film, an electrically insulating film, a partition,a spacer, an inclined member, or the like. The present inventionembraces all of them.

{circle around (1)} Constituent Material

Examples of constituent materials used in the interlayer dielectricinclude acrylic, polycarbonate, polyimide, fluorinated polyimide,benzoguanamine, melamine, cyclic polyolefin, Novolak, polyvinylcinnamate, polyvinyl chloride, polystyrene, phenol, alkyd, epoxy,polyurethane, polyester, maleic acid, and polyamide resins; and cyclicrubber.

In the case that the interlayer dielectric is composed of an inorganicoxide, examples of preferred oxides include silicon oxide (SiO₂ orSiO_(x)), aluminum oxide (Al₂O₃ or AlO_(x)), titanium oxide (TiO₂),yttrium oxide (Y₂O₃ or YO_(x)), germanium oxide (GeO₂ or GeO_(x)), zincoxide (ZnO), magnesium oxide (MgO or MgO_(x)), calcium oxide (CaO),boric acid (B₂O₃), strontium oxide (SrO), barium oxide (BaO), lead oxide(PbO), zirconia (ZrO₂), sodium oxide (Na₂O), lithium oxide (Li₂O), andpotassium oxide (K₂O), wherein x is a value within the range of 1 to 3.

{circle around (2)} Forming Method

The method for forming the interlayer dielectric is not particularlylimited. The interlayer dielectric is preferably deposited by using, forexample, spin coating, casting, screen-printing, sputtering, vapordeposition, chemical vapor deposition (CVD) or ion plating.

{circle around (3)} Water Content

In the same as in the organic luminescence medium, the water content inthe interlayer dielectric is set to preferably 0.05% or less by weight,more preferably 0.03% or less by weight, and still more preferably 0.01%or less by weight.

This is because if the water content in the interlayer dielectric isover 0.05% by weight, contained water promotes oxidization ordeterioration of the upper electrode or the organic luminescence mediumso that dark spots may be easily generated.

The water content in the interlayer dielectric can be measured in thesame way as for the water content in the organic luminescence medium.

(5) Color Changing Medium

A color changing medium may be a color filter, a luminescence film foremitting light having a color different from EL luminescence, or acombination thereof.

{circle around (1)} Color Filter

A color filter is set up to decompose or cut light to adjust color orimprove contrast, and is composed of a colorant layer consisting only ofa colorant or a lamination made by dissolving or dispersing a colorantin a binder resin.

The color filter preferably comprises blue, green and red colorants. Bycombining such a color filter with an organic EL element emitting whitelight, the three primary colors of light, blue, green and red can beobtained so that full color display can be attained.

The color filter is preferably patterned by printing or photolithographyin the same was as for a luminescence medium that will be describedlater.

The water content in the color filter is set to preferably 0.05% or lessby weight, more preferably 0.03% or less by weight, and still morepreferably 0.01% or less by weight in the same way as in the organicluminescence medium.

This is because if the water content in the color filter is over 0.05%by weight, contained water promotes oxidization or deterioration of theupper electrode or the organic luminescence medium so that thegeneration of dark spots may not be easily suppressed.

{circle around (2)} Fluorescence Medium

A fluorescence medium in an active driving type organic EL displaydevice has a function of absorbing luminescence from its organic ELelement to emit fluorescence having a longer wavelength, and is composedof a layered product which fluorescence medium pieces are dimensionallyseparated and arranged. The respective fluorescence medium pieces arepreferably arranged correspondingly to luminescence areas of the organicEL element, for example, positions where the upper and lower electrodescross each other.

Such arrangement makes it possible that the respective fluorescencemedium pieces receive, when the organic luminescence layer emits lightat the positions where the upper and lower electrodes cross each other,the light to take out luminescence having a different color(wavelength). Particularly in the case that the organic EL element emitsblue light and the blue light can be converted to green light and redlight by the fluorescence medium, the three primary colors of light,blue, green and red can be obtained even if the number of the organic ELelement(s) is only one. Thus, full color display can be conventionallyattained.

In the case that the fluorescence medium is made mainly of afluorochrome, the medium is preferably deposited into a film by vacuumevaporation or sputtering through a mask making it possible to obtain adesired pattern of the fluorescence medium.

In the case that the fluorescence medium is made of a fluorochrome and aresin, it is preferred to blend, disperse or dissolve the fluorochromein the resin to prepare a liquid, deposit the liquid into a film by spincoating, roll coating, casting or the like method, and pattern the filminto a desired pattern by photolithography, screen printing or the likemethod to form the fluorescence medium.

The water content in the fluorescence medium is set to preferably 0.05%or less by weight, more preferably 0.03% or less by weight, and stillmore preferably 0.01% or less by weight in the same way as in theorganic luminescence medium.

This is because if the water content in the fluorescence medium is over0.05% by weight, contained water promotes oxidization or deteriorationof the upper electrode or the organic luminescence medium so that thegeneration of dark spots may not be easily suppressed.

The water content in the fluorescence medium can be measured in the sameway as for the water content in the organic luminescence medium.

(6) Examples of the Structure of the Organic EL Display Device

The organic EL display device of the present invention can be made bycombining the above-mentioned basic constituent elements. It is alsopreferred to combine the constituent elements with other constituentelements such as a hole injection layer or an electron injection layer.

The following will describe typical examples of the structure of theorganic EL display device, but the present invention is not limited tothese examples.

-   {circle around (1)} supporting substrate/anode layer/organic    luminescence layer/cathode layer/sealing member-   {circle around (2)} supporting substrate/anode layer/interlayer    dielectric/organic luminescence layer/cathode layer/sealing member-   {circle around (3)} supporting substrate/fluorescence medium/anode    layer/interlayer dielectric/organic luminescence layer/cathode    layer/sealing member-   {circle around (4)} supporting substrate/fluorescence    medium/flattening layer/anode layer/interlayer dielectric/organic    luminescence layer/cathode layer/sealing member-   {circle around (5)} supporting substrate/color filter/anode    layer/interlayer dielectric/organic luminescence layer/cathode    layer/sealing member-   {circle around (6)} supporting substrate/color filter/flattening    layer/anode layer/interlayer dielectric/organic luminescence    layer/cathode layer/sealing member-   {circle around (7)} supporting substrate/color filter/fluorescence    medium/flattening layer/anode layer/interlayer dielectric/organic    luminescence layer/cathode layer/sealing member-   {circle around (8)} supporting substrate/anode layer/organic    luminescence layer/cathode layer/fluorescence medium/sealing member-   {circle around (9)} supporting substrate/anode layer/organic    luminescence layer/cathode layer/color filter/sealing member

FIG. 4 illustrates an organic EL display device 18 that has thestructure {circle around (2)}; FIG. 5, an organic EL display device 18that has the structure {circle around (4)} or {circle around (6)}; FIG.6, an organic EL display device 18 that has the structure {circle around(8)} or {circle around (9)}; FIG. 7, an organic EL display device 18that has the structure {circle around (3)} or {circle around (5)}; FIG.8, an organic EL display device 18 that has the structure {circle around(4)} or {circle around (6)} and is a modification example of the organicEL display device 18 in FIG. 5; and FIG. 9, an organic EL display devicethat has the structure {circle around (8)} or {circle around (9)} and isa modification example of the organic EL display device 18 in FIG. 6.

[Second Embodiment]

As is schematically illustrated in FIG. 16, an apparatus 130 forproducing an organic EL display device in a second embodimentsuccessively comprises:

a first unit (inlet) 21 for carrying a supporting substrate in,

a heating room 71, in a second unit 23, for heating at least thesupporting substrate before forming an organic luminescence medium,thereby performing dehydration treatment,

a cooling room 70, in the second unit 23, for cooling the heatedsupporting substrate,

a third unit 22 for forming the organic luminescence medium and an upperelement,

a buffer unit 72, and

a fourth unit 24 for sealing the periphery of the apparatus with asealing member,

wherein carrying devices (not illustrated) are arranged between therespective units.

Referring appropriately to FIG. 16, the following will describe acharacteristic structure of the producing apparatus 130 of the secondembodiment, and the operation thereof.

1. Structure

(1) First Unit

The first unit (inlet) 21 in the second embodiment has the same contentas the first unit in the first embodiment. Explanation thereof istherefore omitted.

(2) Second unit

The second unit (dehydrating unit) 23 in the second embodiment iscomposed of a heating room 71, a cooling room 70, and a connecting part26 for connecting them to each other. Thus, the second unit 23 isdifferent from that in the first embodiment; wherein the heating roomand the cooling room are arranged in the same room.

In the case that the second unit 23 is separated in this way, asubstrate can be rapidly cooled by transferring the substrate to thecooling room 70 even if the substrate is heated in a reduced-pressuredstate in the heating room 71.

In the case that the second unit 23 is separated in this way, the heatedsubstrate is cooled in the cooling room 70 while a next substrate can beheated in the heating room 71. Thus, productivity can be improved.

The heating room 71 preferably comprises a heating device, a supportingbase, a dry gas circulating device, a vacuum pump, a dew pointhydrometer, and a full automatic absorption/desorption measuring device.The cooling room 70 preferably comprises a heating device, a supportingbase, a dry gas circulating device, a vacuum pump, a dew pointhydrometer, and a full automatic absorption/desorption measuring device.

(3) Third Unit

The third unit (film-deposition unit) 22 in the second embodiment hasthe same content as the third unit in the first embodiment. Explanationthereof is therefore omitted.

(4) Buffer Unit

The buffer unit 72 is arranged between the third and fourth units 22 and24. This case produces an advantage that the vacuum degree in the thirdunit 22 can be more easily adjusted as compared with the case in whichno buffer unit is arranged. In other words, sealing is usually performedin an atmospheric pressure in the fourth unit 24; therefore, if nobuffer unit 72 is arranged, the vacuum degree in the third unit 22 maynot be easily adjusted after the substrate is transferred from the thirdunit 22 in a reduced-pressured state to the fourth unit 24.

By arranging the buffer unit 72 in this way, this unit 72 can be used asa waiting place for the substrate and so on during a time between steps.

By arranging the buffer unit 72 in this way, the film-deposition stateof a resultant organic EL display device, the wiring state thereof, andso on can be beforehand checked with an electric means, a microscope orthe like. Thus, bad products can be taken out, through the buffer unitas a transferring outlet, without being transferred to the fourth unit24, which is performed in the next step.

The buffer unit 72 preferably comprises an inlet, a heating device, acooling device, a supporting base, a dry gas circulating device, avacuum pump, a dew point hydrometer, and so on.

(5) Fourth Unit

The fourth unit (sealing unit) 24 in the second embodiment has the samecontent as the fourth unit in the first embodiment. Explanation thereofis therefore omitted.

2. Operation

In the case that the producing apparatus of the second embodiment isoperated, a substrate is subjected to pre-treatment steps, that is, wetcleaning, infrared ray cleaning and ultraviolet ray cleaning steps, andsubsequently the substrate is put on a given place in the first unit 21.In the pre-treatment steps, it is preferred to form a lower electrode,an interlayer dielectric, a fluorescence medium etc. on the substrate.

Next, a first carrying device (not illustrated) arranged between thefirst unit 21 and the heating room 71 in the second unit 23 is operatedto transfer the substrate to the heating room 71.

Since a shutter between the first unit 21 and the heating room 71 in thesecond unit 23 is opened at the same time when the first carrying deviceis started, the first carrying device can put the substrate passingthrough the shutter in a designated position in the heating room 71while grasping the substrate.

Next, when the-substrate is put on the designated position, the firstcarrying device is returned to a given position in the first unit 21 andthe shutter between the first unit 21 and the heating room 71 in thesecond unit 23 is shut. Heating in the heating room 71 is started.

About dehydrating conditions in the heating, it is preferred thatheating temperature and heating time are, for example, from 50 to 300°C. and from 10 minutes to 24 hours, respectively, in the same way in thefirst embodiment. It is preferred that while the dry gas circulatingdevice is used to adjust the dew point to −10° C. or less with the dewpoint hydrometer, an inert gas is introduced in a flow rate of about 10liters/minute.

Next, the carrying device is used to transfer the dehydrated substrateto the cooling room 70. Accordingly, a shutter between the heating room71 and the cooling room 70 is opened and the carrying device is used totransfer the substrate from the given position in the heating room 71 toa given position in the cooling room 70. The substrate is put on and theshutter between the heating room 71 and the cooling room 70 is closed tostart cooling of the substrate.

Therefore, the substrate can be rapidly cooled by cooling the substratein this way even if the substrate is heated in a reduced pressure statein the heating room 71. The cooling is continued preferably until thetemperature of the substrate is lowered at least near film-depositiontemperature and more preferably until the temperature is lowered near aroom temperature.

Cooling conditions in the cooling room 70 are not particularly limited.For example, cooling temperature and cooling time are from 10 to 40° C.and from 10 minutes to 12 hours, respectively.

Next, it is checked that substrate temperature is lowered to a giventemperature, and subsequently this substrate is transferred to the thirdunit (film-deposition unit) 22 by the carrying device.

The third unit 22 is used to form films of an organic luminescencemedium and an upper electrode. Conditions for the film-deposition may beset to the same as in the first embodiment. Thus, details thereof areomitted.

Next, the carrying unit is used to transfer the substrate on which theorganic luminescence medium and the upper electrode are formed from thethird unit 22 to the buffer unit 72. Namely, the substrate istransferred from the third unit 22 in the reduced-pressured state to agiven position in the buffer unit 72 in a reduced-pressured state whilea shutter 26 arranged therebetween is opened.

The buffer unit 72 is arranged in this way; therefore, the vacuum degreein the third unit 22 can be kept in a given value even if a shutterbetween the buffer unit 72 and the fourth unit 24 is opened or shut atthe time of transferring the substrate up to the fourth unit 24. Inother words, a shutter is also arranged between the buffer unit 72 andthe third unit 22; therefore, the vacuum degree in the third unit 22 canalso be kept by adjusting the vacuum degree in the buffer unit 72 into alevel equivalent to the vacuum degree in the third unit 22.

At last, from the buffer unit 72, the substrate on which the organicluminescence medium and the upper electrode are formed is transferred tothe fourth unit (sealing unit) 24, using the carrying device and openingthe shutter 26 therebetween.

In this case, the same sealing conditions as in the first embodiment arepreferred. Specifically, in the fourth unit 24 as illustrated in FIG.15, it is preferred to seal the substrate and the sealing member bysetting an ultraviolet setting adhesive in the state in these membersare pressed against each other in an inert gas.

[Third Embodiment]

A third embodiment is characterized in that a process for producing anorganic EL display device comprises the following 1st to 4th steps.

By such a production process, the effect of external moisture and so onis excluded because of no exposure to the atmosphere, to make theadjustment of the water content easy. Moreover, the productionefficiency of organic EL display devices can be further improved.

(1) First Step

A first step is the step of putting a substrate before an organicluminescence medium is formed in an inlet, which is the first unit.Dependently on the structure of a resultant organic EL display device,it is preferred that a lower electrode is beforehand formed on thesubstrate.

In a pre-treatment step, it is preferred that an interlayer dielectric(flattening film), a fluorescence medium, and a color filter arebeforehand formed on the substrate before the substrate is put in theinlet, as the first unit, illustrated in FIG. 1.

The formation of the lower electrode on such a supporting substrate ispreferably performed, using a vacuum evaporation device and so on. Theformation can be performed using an apparatus for producing theabove-mentioned third unit.

The respective formations of the interlayer dielectric, the fluorescencemedium and the color filter are preferably performed usingphotolithography.

(2) Second Step

A second step is the step of removing moisture adhering to thesupporting substrate, and removing, when the organic films such as thecolor filter, the fluorescence medium and the interlayer dielectric areformed on the supporting substrate, moisture contained in these organicfilms in the second unit illustrated in FIG. 11. Specifically, it ispreferred to perform the following heating treatment, or this heatingtreatment combined with some other dehydrating treatment.

In the second step, it is also preferred to use a plasma cleaning deviceand an ultrasonic wave cleaning device set in the second unit at bothtimes before and after the dehydrating treatment or either time thereofto remove impurities and dust adhering to the surface of the substrate.

{circle around (1)} Heating Treatment

The heating temperature in the dehydrating step is preferably 40 to 300°C. The reason for this is as follows. If the heating temperature isbelow 40° C., dehydrating efficiency may be markedly lowered. On theother hand, if the heating temperature is over 300° C., thermal damagemay be given to the organic films composed of the fluorescence film andso on.

Therefore, the heating temperature in the dehydrating step is preferably50 to 250° C., and more preferably 60 to 200° C.

Considering the storing environment or the driving environment of theorganic EL display device, it is also preferred to device the heatingtemperature in the dehydrating step. Specifically, the generation ofdark spots can be suppressed in the storing environment or the drivingenvironment by advance treatment at a temperature that is higher thanthe temperature in the storing environment or the driving environment,and preferably a temperature that is at least 10° C. higher than theabove-mentioned temperature.

The dehydrating time in the case that the dehydrating treatment isconducted by heating is affected by the area or thickness of the colorfilter, the fluorescence medium, the first and second interlayerdielectrics and so on, but is preferably a value within the range of,for example, 10 minutes to 12 hours.

The reason for this is as follows. If the dehydrating time is below 10minutes, the dehydrating treatment is insufficient and it may bedifficult to set the water content in the formed organic luminescencemedium to 0.05% or less by weight. On the other hand, if the dehydratingtime is over 12 hours, the treatment time becomes long but resultantadvantages may not vary.

The dehydrating time is therefore set to preferably a value within therange of 30 minutes to 10 hours and more preferably a value within therange of 1 to 6 hours.

{circle around (2)} Introduction of an Inert Gas

It is preferred to introduce an inert gas such as helium, argon ornitrogen into the dehydrating unit in the dehydrating step to performdehydration in such an inert gas. It is more preferred to use nitrogensince production costs fall.

By using such an inert gas, the dehydrating treatment can be conductedwhile reaction and oxidization of the organic layers comprising theorganic luminescence medium, the cathode, and so on are suppressed. Thiscase is therefore preferable.

In order to obtain better dehydrating effect, it is preferred that theinert gas is beforehand dehydrated.

The dehydrating time in the case that the dehydrating treatment isconducted in the inert gas is affected by an inflow speed of the inertgas, or the area and the thickness of the color filter, the fluorescencemedium, the first and second interlayer dielectric, and so on. Thedehydrating time is preferably set to a value within the range of, forexample, 10 minutes to 40 hours.

The reason for this is as follows. If the dehydrating time is below 10minutes, the dehydrating treatment becomes insufficient so that thewater content in the formed organic luminescence medium may not beeasily set to 0.05% or less by weight. On the other hand, if thedehydrating time is over 40 hours, the treatment time becomes long butresultant advantages may not vary.

Accordingly, the dehydrating time is set to preferably 30 minutes to 24hours, and more preferably 1 to 12 hours.

{circle around (3)} Adjustment of the Dew Point

The dew point in the dehydrating step is set to −10° C. or lower topromote the dehydrating treatment of the substrate and so on. This isbecause if the dew point is over −10° C., dehydrating efficiency may bemarkedly lowered.

Therefore, the dew point in the dehydrating step is set to preferably−50° C. or lower, and more preferably a value within the range of −50°C. to −150° C.

The dew point in the dehydrating step can easily be set by adjusting thewater content in the dehydrating unit by introducing the inert gas,lowering the vacuum degree and adjusting the temperature in thedehydrating unit while monitoring the dew point hydrometer.

The dehydrating time in the case that the dew point is set to −10° C. orlower is affected on the area or the thickness of the color filter, thefluorescence medium, the interlayer dielectric and so on. Thedehydrating time is preferably set to, for example, a value within therange of 10 minutes to 40 hours.

The reason for this is as follows. If the dehydrating time is below 10minutes, the dehydrating treatment becomes insufficient so that thewater content in the formed organic luminescence medium may not beeasily set to 0.05% or less by weight. On the other hand, if thedehydrating time is over 40 hours, the treatment time becomes long butresultant advantages may not vary.

Therefore, the dehydrating time is set to more preferably a value withinthe range of 30 minutes to 24 hours, and still more preferably a valuewithin the range of 1 to 12 hours.

{circle around (4)} Adjustment of the Degree of Vacuum

The degree of vacuum in the dehydrating step is preferably a value of13.3 Pa or less. This is because if the degree of vacuum is over 13.3Pa, dehydrating efficiency may be markedly lowered.

Therefore, the vacuum degree is set to more preferably a value of13.3×10⁻⁴ Pa or less, and still more preferably a value within the rangeof 13.3×10⁻⁴ to 13.3×10⁻⁸ Pa.

The dehydrating time in the case that the vacuum degree in thedehydrating step is set to 13.3×10⁻⁴ Pa or less is affected by the areaor the thickness of the color filter, the fluorescence medium, theinterlayer dielectric and so on. The dehydrating time is preferably setto, for example, a value within the range of 10 minutes to 12 hours.

The reason for this is as follows. If the dehydrating time is below 10minutes, the dehydrating treatment becomes insufficient so that thewater content in the formed organic luminescence medium may not beeasily set to 0.05% or less by weight. On the other hand, if thedehydrating time is over 12 hours, the treatment time becomes long butresultant advantages may not vary.

Therefore, the dehydrating time is set to more preferably a value withinthe range of 30 minutes to 10 hours, and still more preferably a valuewithin the range of 1 to 6 hours.

(3) Third Step

A third step is the step of forming an organic luminescence medium andan upper electrode in the third unit 22 illustrated in FIGS. 12 and 13.

The formation of the organic luminescence medium and the upper electrodeis preferably performed by using a method making film-deposition in adry state possible, such as vacuum evaporation or sputtering.

The following will specifically describe a method of depositing anelectron injected area 14 on the substrate 203, using the vacuumdeposition device 201 explained about the third unit.

The planar and square substrate 203 as illustrated in FIG. 13 is firstprepared and then this substrate 203 is engaged with the holder unit 215of the substrate holder 211 to be made into a horizontal state.

Next, in order to form the electron injected area 14, an electrontransporting compound and an electron injecting material (reducingdopant) are filled into the evaporation sources 212A and 212D,respectively, which are adjacent to each other on the imaginary circle221, and then the pressure in the vacuum tank 210 is reduced into agiven vacuum degree, for example, 13.3×10⁻⁵ Pa (1.0×10⁻⁶ Torr) by theexhausting means.

Next, the evaporation sources 212A and 212D are heated to evaporate theelectron transporting compound and the reducing dopant simultaneouslyfrom the evaporation sources 212A and 212D, respectively. Moreover, themotor 214 is rotation-driven to rotate the substrate 203 around therotation axis 213A at a given rate, for example, 1 to 100 rpm(revolutions per minute). In this way, the substrate 203 is rotated onits axis and simultaneously the electron transporting compound and thereducing dopant are co-evaporated to deposit the electron injected area14.

As illustrated in FIG. 13, at this time the evaporation sources 212A and212D are arranged a given distance M apart from the rotation axis 213Aof the substrate 203 in the horizontal direction. Therefore, by therotation of the substrate 203, the incident angle of the electrontransporting compound and the reducing dopant to the substrate 203 canbe regularly changed.

For this reason, it is possible to adhere the evaporation materialsuniformly to substrate 203, and deposit surely a thin film having aneven composition of the evaporation materials, for example, a thin filmhaving a concentration unevenness of ±10% (mole conversion) in the filmsurface of the electron injected area 14.

By performing the vapor-deposition in this way, it is unnecessary torevolute the substrate 203. Thus, no space or facilities for therevolution are necessary so that the film-deposition can be economicallyperformed in a minimum space. The revolution of the substrate means thatthe substrate is rotated around a rotation axis which is present outsidethe substrate. In this case, a wider space is necessary than in the casethat the substrate rotates on its axis.

(4) Fourth Step

A fourth step is the step of covering the periphery of the organic ELelement obtained at the time of the finish of the third step with asealing member, and is preferably performed using the fourth unitillustrated in FIG. 15.

Therefore, the fourth step is preferably the step of covering theperiphery of the organic EL element with the sealing member while a drygas, for example, dry nitrogen or dry argon is circulated at a flow rateof 0.01 to 6 m³/minute in the fourth unit, and then sealing theperiphery with an adhesive or the like while the sealing member ispressed.

In the case that a radical setting adhesive or a cation setting adhesiveis used herein, the adhesive can be set for a short time, that is, for10 seconds or less by radiating ultraviolet rays with an adhesivesetting exposure equipment.

In the case that a thermosetting adhesive is used, the adhesive can beset for a time of 30 seconds to 1 hour by heating at 50–150° C. with ahot plate.

In the case that a moisture setting adhesive is used, the adhesive canbe gradually set by exposing the adhesive to the open air after thesealing.

(5) Combination of the Respective Steps

The following will describe examples of production of an organic ELdisplay device by combination the above-mentioned 1st to 4th steps. Thepresent invention is not limited to these examples.

{circle around (1)} First Combination

A first combination is steps of using a producing apparatus wherein thefourth unit is connected to the third unit,

carrying a supporting substrate into the first unit,

using the carrying unit to transfer the carried supporting substratefrom the first unit to the second unit,

heating the transferred supporting substrate in the second unit toperform dehydrating treatment,

using the carrying device to transfer the dehydrated supportingsubstrate from the second unit to the third unit,

forming an organic luminescence medium and an upper electrode in thethird unit,

using the carrying device to transfer the supporting substrate on whichthe organic luminescence medium and the upper electrode are formed fromthe third unit to the fourth unit, and

sealing the periphery with a sealing member in the fourth unit.

By carrying out such steps, the water content in the organicluminescence medium can easily be adjusted after the organic EL displaydevice is fabricated. Thus, the organic EL display device wherein thegeneration of dark spots is greatly reduced can be effectively obtained.

{circle around (2)} Second Combination

A second combination is steps of using a producing apparatus wherein thefourth unit is connected to the first unit; and

using, in the first combination, the carrying device to transfer thesupporting substrate on which the organic luminescence medium and theupper electrode are formed from the third unit to the first unit, and

sealing the periphery with a sealing member in the fourth unit.

By carrying out such steps, the water content in the organicluminescence medium can easily be adjusted after the organic EL displaydevice is fabricated. Thus, the organic EL display device wherein thegeneration of dark spots is greatly reduced can be effectively obtained.

{circle around (3)} Third Combination

A third combination is steps of using a producing apparatus wherein thefourth unit is in common with the second unit; and

using, in the first combination, the carrying device to transfer thesupporting substrate on which the organic luminescence medium and theupper electrode are formed from the third unit to the fourth unit, whichis in common with the second unit, through the first unit, and sealingthe periphery with a sealing member in the fourth unit.

By carrying out such steps, the water content in the organicluminescence medium can easily be adjusted after the organic EL displaydevice is fabricated. Thus, the organic EL display device wherein thegeneration of dark spots is greatly reduced can be effectively obtained.

{circle around (4)} Fourth Combination

A fourth combination is steps of using, in any one of the 1st to 3rdcombinations, the carrying device to transfer the dehydrated supportingsubstrate from the second unit to the first unit, cooling the supportingsubstrate, and transferring the supporting substrate to the third unit.

By cooling the dehydrated supporting substrate with the first unit inthis way, the supporting substrate can be effectively cooled even if thedehydrating treatment is performed in a reduced pressured state in thesecond unit. Thus, the time until the substrate is transferred to thethird unit can be shortened.

By cooling the dehydrated supporting substrate with the first unit inthis way, another substrate can be simultaneously dehydrated in thesecond unit. Thus, production efficiency can be improved.

{circle around (5)} Fifth Combination

A fifth combination is step of forming, in any one of the 1st to 4thcombinations, an organic luminescence medium in the third unit,transferring the supporting substrate on which the organic luminescencemedium is formed from the third unit to the second unit with thecarrying unit, dehydrating the substrate, and transferring the substrateagain from the second unit to the third unit to form an upper electrode.

By carrying out such steps, the water content in the organicluminescence medium can more easily be adjusted after the organic ELdisplay device is fabricated. Thus, the organic EL display devicewherein the generation of dark spots is greatly reduced can beeffectively obtained.

{circle around (6)} Sixth Combination

A sixth combination is as follows: in any one of 1st–5th combinations,the second unit comprises a heating room and a cooling room. In theheating room, the supporting substrate is heated to be dehydrated. Inthe cooling room, the dehydrated supporting substrate is cooled.

By carrying out such steps, the water content in the organicluminescence medium can more easily be adjusted after the organic ELdisplay device is fabricated. Thus, the organic EL display devicewherein the generation of dark spots is greatly reduced can beeffectively obtained.

EXAMPLES Example 1

(1) Production of an Organic EL Element

{circle around (1)} Formation of an Anode (Lower Electrode)

An ITO film 130 nm in thickness was formed on an entire surface of aglass substrate (OA2 glass, made by Nippon Electric glass Co., Ltd.) 112mm in length, 143 mm in width and 1.1 mm in thickness, using asputtering apparatus. A positive resist HPR204 (made by Fuji HuntElectronics Technology Co., Ltd.) was applied to the ITO film byspin-coating, and this resist was dried at a temperature of 80° C. for10 minutes.

Next, the resultant was subjected to contact-exposure to light, using ahigh-pressure mercury light, through a photomask having a stripe pattern(line width: 90 μm, and gap width: 20 μm). The light exposure was set to100 mJ/cm². As a developer, tetramethylammoniumhydroxide (TMAH) was usedto develop the exposed portions.

Next, the resultant was subjected to post-baking at a temperature of130° C., using an oven. As an etchant, an aqueous solution of hydroboricacid (concentration: 47% by weight) was used to etch the ITO film.Thereafter, an exfoliating liquid N303 (made by Nagase & Co., Ltd.) wasused to remove the positive resist. Thus, an ITO stripe pattern (numberof lines: 960) was formed as an anode (lower electrode).

{circle around (2)} Formation of a First Intermediate Insulating Layer

Next, a negative resist V259PA (made by Nippon Steel Chemical Co., Ltd.)was applied onto the ITO pattern by spin-coating. This resist was driedat a temperature of 80° C. for 10 minutes and the resultant wassubjected to contact-exposure to light, using the high-pressure mercurylight, through a photomask having a stripe pattern (line width: 90 μm,and gap width: 20 μm), which crossed the ITO pattern. The light exposurewas set to 100 mJ/cm². Next, as a developer, TMAH was used to developthe unexposed portions. The resultant was subjected to post-baking at atemperature of 160° C., using the oven. Thus, a first interlayerdielectric (an opening-in the ITO: 70 μm×290 μm) was formed.

{circle around (3)} Formation of a Second Intermediate Insulating Layer

A negative resist ZPN1100 (made by Nippon Zeon Co., Ltd.) was applied tothe first interlayer dielectric by spin-coating, and this resist wasdried at a temperature of 80° C. for 10 minutes, and subsequently theresultant was subjected to contact-exposure to light, using thehigh-pressure mercury light, through a photomask having a stripe pattern(line width: 20 μm, and gap width: 310 μm), which was parallel to theITO pattern as the lower electrode. The light exposure was set to 100mJ/cm².

Next, as a developer, TMAH was used to develop the unexposed portions.The resultant was subjected to post-baking at a temperature of 160° C.,using an oven. Thus, a second interlayer dielectric (line width: 20 μm,gap width: 310 μm, and thickness: 5 μm) as partitions was prepared.

{circle around (4)} Dehydrating Step

Next, the glass substrate on which the ITO pattern and so on were formed(which may be referred merely to the glass substrate) was cleaned withisopropyl alcohol and ultraviolet rays. Thereafter, the glass substratewas put on a given position in the first unit (inlet) of the producingapparatus illustrated in FIG. 3.

Next, the carrying device (movable arm) set up to the first unit wasused to transfer the glass substrate from the first unit to the secondunit (dehydrating unit).

A hot plate was used to heat the glass substrate in the first unit to60° C. While dry nitrogen was introduced thereto in this state, the dewpoint was lowered to −50° C. and the substrate was allowed to stand forabout 2 hours. Thus, moisture in the first and second interlayerdielectrics and moisture adhering to the surface of the glass substrateand so on were removed.

{circle around (5)} Formation of an Organic Luminescence Medium

Next, the heating of the hot plate was stopped so that the temperatureof the glass substrate dropped to room temperature. Thereafter, thecarrying device set in the first unit was used to transfer thedehydrated substrate from the second unit to the third unit (vacuumdeposition device) via the first unit and fix the substrate to thesubstrate holder illustrated in FIG. 13.

Heating boards in the third unit were beforehand filled with thefollowing materials: hole injection material:4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA),and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]-biphenyl(NPD)

organic luminescence material: 4,4′-bis(2,2-diphenylvinyl) terphenyl(DPVTP)

electron injecting material: tris(8-quinolinol)aluminum (Alq)

upper electrode material: Al—Li alloy (Li concentration: 10% by atom)

Next, the vacuum degree in the third unit was reduced to 665×10⁻⁷ Pa,and an organic luminescence medium (a hole injection layer, an organicluminescence layer and an electron injection layer) and an upperelectrode were successively deposited without breaking from theformation of the hole injection layer to the formation of the upperelectrode, in such a manner that the following vapor deposition rate andthickness would be generated.

-   MTDATA: vapor deposition rate=0.1 to 0.3 nm/sec., thickness=60 nm,-   NPD: vapor deposition rate=0.1 to 0.3 nm/sec., thickness=20 nm,-   DPVTP: vapor deposition rate=0.1 to 0.3 nm/sec., thickness=40 nm,-   Alq: vapor deposition rate=0.1 to 0.3 nm/sec., thickness=20 nm, and-   Al—Li: vapor deposition rate=0.5 to 1.0 nm/sec., thickness=150 nm.    {circle around (6)} Sealing Step

Next, the carrying device set in the first unit was used to transfer theglass substrate on which the organic luminescence medium and the upperelectrode were formed from the third unit to the fourth unit (sealingunit), which was in common with the second unit, via the first unit.

In the fourth unit, a sealing glass substrate (blue glass, made byGeomatec Co., Ltd.) was deposited on the upper electrode, andsubsequently a photo-curing type adhesive TB3102 (made by Three BondCo., Ltd.). was used to seal the periphery thereof by hardening theadhesive through ultraviolet ray exposure. Thus, an organic EL displaydevice for measuring luminescence performance was produced.

Under the same production conditions, an organic EL display device formeasuring the water content and an organic EL display device for adurability test were produced.

(2) Evaluation of the Organic EL Device

{circle around (1)} Measurement of the Water Content

The resultant organic EL display device was decomposed inside a dry boxwherein dry nitrogen was continuously introduced, and a spatula was usedto collect the organic luminescence medium. (The medium comprised a partof the intermediate insulating layer. The same fact is correspondinglyapplied to the following.) Moreover, a full automaticabsorption/desorption measuring device IGA SORP (made by HidenAnalytical Ltd. in England) set in the dry box was used to measure theweight of the organic luminescence medium. As a result, the weight A ofthe organic luminescence medium was 43.9194 mg.

Next, the collected organic luminescence medium was heated at 75° C. inthe dry box for 30 minutes and then the weight of the heated medium wasmeasured with the full automatic absorption/desorption measuring device.As a result, the weight B of the heated organic luminescence medium was43.9190 mg.

The resultant weights A and B were introduced into the calculatingequation to calculate the water content (W (%)) in the organicluminescence medium. As a result, the water content (W) in the organicluminescence medium was 0.0009% by weight.

Namely, it was demonstrated that the setting of the second unit(dehydrating step) before the formation of the organic luminescencemedium to remove moisture from the surface of the supporting substrateand the first and second interlayer dielectrics was an effective mannerfor lowering the water content in the organic luminescence medium.

{circle around (2)} Measurement of Luminescence Performance

A DC voltage of 10 V was applied between the lower electrode (ITOpattern, anode) and the upper electrode (cathode) in the resultantorganic EL display device to cause respective pixels (about 230,000pixels), which were portions where the electrode patterns crossed eachother, to emit light. A Chroma Meter CS100 (made by Minolta Co., Ltd.)was used to measure the luminescence brightness so that a value of 300cd/m² was obtained. The numerical aperture, which is the percentage ofthe area of the pixels in the total area of the luminescence surface,was 56%.

Under the same conditions, the respective pixels of the organic ELdisplay device were caused to emit light and then the CIE chromaticitywas measured so that blue luminescence whose CIEx was 0.15 and whoseCIEy was 0.18 in the CIE chromaticity coordinates was obtained.

{circle around (3)} Durability Test

The resultant two organic EL display devices were allowed to stand atroom temperature (25° C.) in the atmosphere and at 75° C. in athermostat, respectively, for two weeks. Thereafter, respective pixelsof the organic EL display device were caused to emit light under theabove-mentioned voltage condition to measure the area of region emittingthe light appropriately, where no dark spot was generated. (This regionwill be referred to as the luminescence region hereinafter.) The area ofthe luminescence region was compared with the area of the luminescenceregion before the storage, to evaluate durability.

When the area of the luminescence region before the storage was regardedas 1, the area of the luminescence region after the storage was 0.98 inthe case that the organic EL display device was allowed to store at roomtemperature (25° C.) in the atmosphere. The area of the luminescenceregion after the storage was 0.97 in the case that the organic ELdisplay devices was allowed to stand at 75° C. in the thermostat.

Namely, it was demonstrated that by setting the water content in theorganic luminescence medium to a given value (0.05% by weight) or less,it was possible to suppress a reduction in the luminescence area by thegeneration of dark spots for a long time not only under the condition ofroom temperature (25° C.) in the atmosphere but also under the conditionof the high temperature of 75° C.

Comparative Example 1

An organic EL display device was produced and evaluated in the samemanner as in Example 1 except that no dehydrating treatment wasconducted by the second unit before the organic EL element was formed.The obtained results are shown in Table 1.

As can be understood from the results, the water content in the organicluminescence medium was 0.0713% by weight, and could not be lowered to0.05% or less by weight since no dehydrating step was used.

In the case that the resultant organic EL display device was allowed tostand at room temperature (25° C.) in the atmosphere for 2 weeks and at75° C. in a thermostat for 2 weeks, the luminescence area ratios (theabove-mentioned areas of the luminescence region) were 0.80 and 0.55,respectively.

Namely, it was demonstrated that because no dehydrating treatment wasconducted before the formation of the organic element, it was impossibleto set the water content in the organic luminescence medium to 0.05% orless by weight and it was difficult to suppress a reduction in theluminescence area by the generation of dark spots under the condition ofroom temperature (25° C.) in the atmosphere and under the condition ofthe high temperature of 75° C.

Example 2

An organic EL display device was produced and evaluated in the samemanner as in Example 1 except that a red filter and a fluorescencemedium were formed before the formation of the organic EL element andfurther the material for forming the lower electrode was changed fromITO to IZO. The obtained results are shown in Table 1.

As can be understood from the results, the water content in the organicluminescence medium was 0.0385% by weight, which was somewhat higherthan that of Example 1, because the step of forming the red filter andthe fluorescence medium would be necessary.

However, even if the resultant organic EL display device was allowed tostand at room temperature (25° C.) in the atmosphere for two weeks andat 75° C. in a thermostat for two weeks, the luminescence area ratioswere 0.9 or more, respectively. Namely, it was demonstrated that it waspossible to suppress the generation of dark spots in Example 2 byconducting the dehydrating treatment in the dehydrating step.

Comparative Example 2

An organic EL display device was produced and evaluated in the samemanner as in Example 2 except that no dehydrating treatment wasconducted by the second unit before the organic EL element was formed.The obtained results are shown in Table 1.

As can be understood from the results, the water content in the organicluminescence medium was 0.3215% by weight, and could not be lowered to0.05% or less by weight since no dehydrating step was used.

In the case that the resultant organic EL display device was allowed tostand at room temperature (25° C.) in the atmosphere and at 75° C. in athermostat, the luminescence area ratios were 0.33 and 0.15,respectively. Namely, it was demonstrated that because no dehydratingtreatment was conducted before the formation of the organic element, itwas impossible to set the water content in the organic luminescencemedium to 0.05% or less by weight and it was difficult to suppress areduction in the luminescence area by the generation of dark spots underthe condition of room temperature (25° C.) in the atmosphere and underthe condition of the high temperature of 75° C.

TABLE 1 Comparative Comparative Example 1 Example 1 Example 2 Example 1Organic EL Color filter None None Formed Formed display Fluorescencemedium None None Formed Formed device Anode ITO ITO IZO IZO (lowerelectrode) Hole injection layer MTDATA/ MTDATA/ MTDATA/ MTDATA/ NPD NPDNPD NPD Luminescence layer DPVTP DPVTP DPVTP DPVTP Electron injectionlayer Alq Alq Alq Alq Cathode Al/Li Al/Li Al/Li Al/Li (upper electrode)Sealing glass Formed Formed Formed Formed substrate Dehydrating step Dewpoint None Dew point: None −50° C., N₂, −50° C., N₂, heating to heatingto 60° C. 60° C. Initial {circle around (1)} Water content 0.0009 0.07130.0009 0.3215 {circle around (2)} Luminescence 300 300 70 70 brightness{circle around (3)} CIEx 0.15 0.15 0.65 0.65 {circle around (4)} CIEy0.18 0.18 0.32 0.32 Room {circle around (5)} Luminescence 0.98 0.80 0.940.33 temperature area ratio for 2 weeks {circle around (6)} Luminescence294 240 65.8 23.1 brightness (cd/m²) 75° C. for {circle around (7)}Luminescence 0.97 0.55 0.91 0.15 2 weeks area ratio {circle around (8)}Luminescence 291 165 63.7 10.5 brightness (cd/m²) Unit: Water content (%by weight) Luminescence brightness (cd/m²)

Example 3

An organic EL display device was produced and evaluated in the samemanner as in Example 1 except that a producing apparatus comprising adehydrating unit composed of a heating room and a cooling room asillustrated in FIG. 16 was used instead of the producing apparatusillustrated in FIG. 3.

In other words, the glass substrate on which the first and secondinterlayer dielectrics were formed was subjected to cleaning withisopropyl alcohol and ultraviolet rays, and then this glass substratewas put in a given position in the first unit (inlet) of the producingapparatus illustrated in FIG. 16.

Next, the carrying device (movable arm) set in the first unit was usedto transfer the glass substrate from the first unit to the heating roomof the second unit (dehydrating unit). A hot plate was used to heat theglass substrate in the heating room to 60° C. While dry nitrogen wasintroduced thereto in this state, the dew point was lowered to −50° C.The glass substrate was allowed to stand for 2 hours to remove moisturein the first and second interlayer dielectrics and moisture adhering tothe surface of the glass substrate and so on.

Next, the carrying device (movable arm) was used to transfer the glasssubstrate that was still heated to 60° C. from the heating room to thecooling room. While dry nitrogen was introduced thereto, the glasssubstrate in the cooling room was brought into contact with a stainlesssteel cooling plate (temperature: 10° C.) for 30 minutes to lower thetemperature of the glass substrate to room temperature (25° C.).

As a result, the water content in the organic luminescence medium in theorganic EL display device obtained in Example 3 was 0.0009% by weight.In the same way in Example 1, the organic EL display device was causedto emit light so that the luminescence brightness was 300 cd/m² and blueluminescence whose CIEx was 0.15 and whose CIEy was 0.18 was obtained.

Even if the resultant organic EL display device was allowed to stand atroom temperature (25° C.) in the atmosphere for 2 weeks and at a hightemperature of 75° C. for 2 weeks, the ratios of the resultantluminescence areas to the initial value thereof were 0.98 and 0.97,respectively.

Namely, it was demonstrated that by setting the water content in theorganic luminescence medium to a given value or less through thedehydrating treatment in the dehydrating step in Example 3, it waspossible to suppress the generation of dark spots.

It was also made sure that since the dehydrating unit composed of theheating room and the cooling room was used, the processing for loweringthe substrate after the dehydrating treatment, which required about 2hours in Example 1, required only 30 minutes; thus, the processing couldbe very promptly performed and the organic EL display device could beeffectively produced.

Example 4

An organic EL display device was produced and evaluated in the samemanner as in Example 1 except that the substrate dehydrated before thefilm-deposition was cleaned with plasma in the third unit.

In other words, argon and oxygen were used as plasma gas, and the flowrates thereof were set to 200 sccm and 75 sccm, respectively. Moreover,the pressure at the time of the plasma cleaning was set to 1.18 Pa, theoutput of the high frequency wave (13.56 MHz) was set to 50 W, and thetime for the plasma cleaning was set to 10 minutes.

As a result, the water content in the organic luminescence medium in theorganic EL display device obtained in Example 4 was 0.0009% by weight.In the same way in Example 1, the organic EL display device were causedto emit light so that the luminescence brightness was 300 cd/m² and blueluminescence whose CIEx was 0.15 and whose CIEy was 0.18 was obtained.

Even if the resultant organic EL display device was allowed to stand atroom temperature (25° C.) in the atmosphere for 2 weeks and at a hightemperature of 75° C. for 2 weeks, the ratios of the resultantluminescence areas to the initial value thereof were 0.99 and 0.98,respectively.

Namely, it was demonstrated that by setting the water content in theorganic luminescence medium to a given value or less through thedehydrating treatment in the dehydrating step in Example 4 and cleaningthe substrate dehydrated before the film-deposition with plasma, it waspossible to suppress the generation of dark spots more effectively.

INDUSTRIAL APPLICABILITY

As described above, according to the apparatus for producing an organicEL display device of the present invention, by setting the second unitfor dehydrating a substrate and so on positively, the water content inits organic luminescence medium can be lowered. Specifically, an organicEL display device having a water content of 0.05% or less by weight canbe effectively obtained. Therefore, even if the organic EL displaydevice is driven for a long time not only under a room temperaturecondition but also under a high temperature condition, the generation ofdark spots, which are non-luminescence areas, can be effectivelysuppressed.

According to the organic EL display device producing apparatus of thepresent invention, by connecting the second unit for conductingdehydrating treatment to the third unit for conducting a film-depositionstep through the first unit as an inlet, conveniences and productiveefficiency can be improved.

According to the organic EL display device producing apparatus of thepresent invention, by using an evaporation device having pluralevaporation sources in the third unit for conducting a film-depositionstep or by making the second unit for conducting dehydrating treatmentin common with the fourth unit for performing a sealing step, theorganic EL display device can easily be made small-sized.

According to the process for producing an organic EL display device ofthe present invention, by using the step of dehydrating a substrate andso on, an organic EL display device wherein the generation of dark spotsand the like can be suppressed can be effectively obtained even if theorganic EL display device is driven in a high temperature environmentfor a long time.

Therefore, an organic EL display device which is superior in enduranceand has a size of 2 to 30 inches can be effectively obtained. Thus, thedevice can be widely used as a display device for the people'slivelihood, such as a small-sized display portable terminal (portabletelephone), a display device adapting for car, an instrument paneldevice, a car navigator, a notebook-size personal computer; or a displaydevice for industries, such as an office automation display device, afactory automation display device or a monitor for measurement devices.

1. An apparatus for producing an organic EL display device thatcomprises at least a supporting substrate, a lower electrode, an organicluminescence medium and an upper electrode, the periphery of the devicebeing sealed with a sealing member, the apparatus comprising: a firstunit for carrying a supporting substrate, a second unit for heating atleast a supporting substrate before forming an organic luminescencemedium on a substrate, for dehydration treatment, a third unitcomprising at least one device selected from the group consisting of avapor depositing device, a sputtering device, an ion plating device, anelectron beam evaporation device, a chemical vapor deposition device, ametal oxide chemical vapor deposition device, and a plasma enhancedchemical vapor deposition device, for forming an organic luminescencemedium and an upper electrode, and a fourth unit for sealing theperiphery of such an organic EL display device with a sealing member,and carrying units for transferring a supporting substrate between therespective units, wherein the first unit is located between the secondunit and the third unit.
 2. The organic EL display device producingapparatus according to claim 1, wherein the second unit comprises aheating room and a cooling room.
 3. The organic EL display deviceproducing apparatus according to claim 1, wherein the second unitcomprises at least one of an inert gas circulating device, apressure-reducing device, and a cooling device.
 4. The organic ELdisplay device producing apparatus according to claim 1, wherein thefirst unit comprises at least one of an inert gas circulating device, apressure-reducing device and a cooling device.
 5. The organic EL displaydevice producing apparatus according to claim 1, wherein the fourth unitis connected to the first unit.
 6. The organic EL display deviceproducing apparatus according to claim 1, wherein the second unit isintegral with the fourth unit.
 7. The organic EL display deviceproducing apparatus according to claim 1, wherein the third unit furthercomprises a vacuum evaporation device having plural evaporation sourcesfor evaporating plural samples simultaneously or successively.
 8. Theorganic EL display device producing apparatus according to claim 1,wherein the third unit comprises a buffer room, a vacuum evaporationdevice, and a sputtering device.
 9. The organic EL display deviceproducing apparatus according to claim 1, wherein the third unit furthercomprises a plasma-cleaning device.